diff --git a/lib/ui.js b/lib/ui.js
index f1b1b61..2497482 100644
--- a/lib/ui.js
+++ b/lib/ui.js
@@ -3,6 +3,7 @@ import { createIcon, resolveIcon } from "./ui/icon";
 import { createCheckbox, resolveCheckbox } from "./ui/checkbox";
 import { setTooltip, resolveTooltip } from "./ui/tooltip";
 import Dropdown from "./ui/dropdown";
+import Grid from "./ui/grid";
 
 export {
   // icon
@@ -15,5 +16,7 @@ export {
   setTooltip,
   resolveTooltip,
   // dropdown
-  Dropdown
+  Dropdown,
+  // grid
+  Grid
 }
diff --git a/lib/ui/checkbox.js b/lib/ui/checkbox.js
index ef4f26d..af90e15 100644
--- a/lib/ui/checkbox.js
+++ b/lib/ui/checkbox.js
@@ -14,8 +14,7 @@ function fillCheckbox(container, type, label) {
     }
 }
 
-function createCheckbox(opts) {
-    opts ??= {};
+function createCheckbox(opts = {}) {
     const container = document.createElement('label');
     container.className = 'checkbox-wrapper';
     const input = document.createElement('input');
@@ -56,8 +55,7 @@ function createCheckbox(opts) {
     return container;
 }
 
-function resolveCheckbox(container, legacy) {
-    container ??= document.body;
+function resolveCheckbox(container = document.body, legacy) {
     if (legacy) {
         const checks = container.querySelectorAll('input[type="checkbox"]');
         for (let chk of checks) {
diff --git a/lib/ui/dropdown.js b/lib/ui/dropdown.js
index f2c7fac..3aa37a6 100644
--- a/lib/ui/dropdown.js
+++ b/lib/ui/dropdown.js
@@ -97,8 +97,7 @@ class Dropdown {
     onselected;
     onexpanded;
 
-    constructor(options) {
-        options ??= {};
+    constructor(options = {}) {
         options.searchplaceholder ??= r('searchHolder', 'Search...');
         options.textkey ??= 'text';
         options.valuekey ??= 'value';
@@ -287,8 +286,7 @@ class Dropdown {
 
     get #expanded() { return this.#container?.style.visibility === 'visible' }
 
-    #dropdown(flag) {
-        flag ??= true;
+    #dropdown(flag = true) {
         const options = this.#options;
         const textkey = options.textkey;
         let panel = this.#container;
@@ -472,8 +470,7 @@ class Dropdown {
         }
     }
 
-    static resolve(dom) {
-        dom ??= document.body;
+    static resolve(dom = document.body) {
         const selects = dom.querySelectorAll('select');
         for (let sel of selects) {
             const source = [...sel.children].map(it => {
diff --git a/lib/ui/grid.js b/lib/ui/grid.js
new file mode 100644
index 0000000..2f4e649
--- /dev/null
+++ b/lib/ui/grid.js
@@ -0,0 +1,607 @@
+import { isMobile, global, nullOrEmpty, throttle, truncate, isPositive } from "../utility";
+import { r } from "../utility/lgres";
+import { createIcon } from "../ui/icon";
+import { createCheckbox } from "../ui/checkbox";
+
+const ColumnChangedType = {
+    Reorder: 'reorder',
+    Resize: 'resize',
+    Sort: 'sort'
+};
+const RefreshInterval = isMobile() ? 32 : 0;
+const MaxColumnBit = 10;
+const MaxColumnMask = 0x3ff;
+const RedumCount = 4;
+const MiniDragOffset = 4;
+const MiniColumnWidth = 50;
+
+class GridColumn {
+    static create() { return document.createElement('span') }
+
+    static setValue(element, val) { element.innerText = val }
+
+    static getValue(element) { return element.innerText }
+}
+
+class GridInputColumn extends GridColumn {
+    static createEdit(trigger) {
+        const input = document.createElement('input');
+        input.setAttribute('type', 'input');
+        if (typeof trigger === 'function') {
+            input.addEventListener('change', trigger);
+        }
+        return input;
+    }
+
+    static setValue(element, val) { element.value = val }
+
+    static getValue(element) { return element.value }
+
+    static setEnabled(element, enabled) { element.disabled = enabled !== false }
+}
+
+class GridDropdownColumn extends GridColumn {
+}
+
+class GridCheckboxColumn extends GridColumn {
+    static createEdit(trigger) {
+        const check = createCheckbox({
+            onchange: typeof trigger === 'function' ? trigger : null
+        });
+        return check;
+    }
+
+    static setValue(element, val) { element.querySelector('input').checked = val }
+
+    static getValue(element) { return element.querySelector('input').checked }
+
+    static setEnabled(element, enabled) { element.querySelector('input').disabled = enabled !== false }
+}
+
+const ColumnTypes = {
+    0: GridColumn,
+    1: GridInputColumn,
+    2: GridDropdownColumn,
+    3: GridCheckboxColumn
+};
+
+class Grid {
+    #source;
+    #currentSource;
+    #parent;
+    #el;
+    #refs;
+    #rendering;
+    #selectedColumnIndex = -1;
+    #selectedIndexes;
+    #startIndex = 0;
+    #needResize;
+    #containerHeight;
+    #bodyClientWidth;
+    #rowCount = -1;
+    #overflows;
+    #scrollTop;
+
+    columns = [];
+    langs = {
+        all: r('allItem', '( All )'),
+        ok: r('ok', 'OK'),
+        reset: r('reset', 'Reset')
+    };
+    virtualCount = 100;
+    rowHeight = 27;
+    filterRowHeight = 26;
+    height;
+    multiSelect = false;
+    allowHtml = false;
+    holderDisabled = false;
+    window = global;
+    sortIndex = -1;
+    sortDirection = 'asc';
+
+    willSelect;
+    selectedRowChanged;
+    cellDblClicked;
+    cellClicked;
+    rowDblClicked;
+    columnChanged;
+
+    static ColumnTypes = {
+        Common: 0,
+        Input: 1,
+        Dropdown: 2,
+        Checkbox: 3
+    };
+
+    constructor(container) {
+        this.#parent = container;
+    }
+
+    get source() { return this.#source; }
+    set source(list) {
+        if (this.#el == null) {
+            throw new Error('grid has not been initialized.')
+        }
+        this.#source = list;
+        // TODO: filter to currentSource;
+        this.#currentSource = list;
+        this.#containerHeight = list.length * this.rowHeight;
+        this.#overflows = {};
+        this.#selectedColumnIndex = -1;
+        this.#selectedIndexes = [];
+        this.#startIndex = 0;
+        this.#scrollTop = 0;
+        this.#refs.body.scrollTop = 0;
+        this.#refs.bodyContent.style.top = '0px';
+        this.#refs.bodyContainer.style.height = `${this.#containerHeight}px`;
+        this.#rowCount = -1;
+
+        if (this.sortIndex >= 0) {
+            this.sortColumn(true);
+        } else {
+            this.resize();
+        }
+    }
+    get virtual() { return this.#currentSource?.length > this.virtualCount }
+    get sortKey() { }
+    get selectedIndexes() { return this.#selectedIndexes }
+    set selectedIndexes(indexes) { }
+    get selectedIndex() { }
+    get loading() { return this.#refs.loading?.style.visibility === 'visible' }
+    set loading(flag) {
+        if (this.#refs.loading == null) {
+            return;
+        }
+        if (flag === false) {
+            this.#refs.loading.style.visibility = 'hidden';
+            this.#refs.loading.style.opacity = 0;
+        } else {
+            this.#refs.loading.style.visibility = 'visible';
+            this.#refs.loading.style.opacity = 1;
+        }
+    }
+    get scrollTop() { return this.#refs.body?.scrollTop; }
+    set scrollTop(top) {
+        if (this.#refs.body == null) {
+            return;
+        }
+        this.#refs.body.scrollTop = top;
+        this.reload();
+    }
+
+    init(container = this.#parent) {
+        this.#el = null;
+        this.#refs = {};
+        this.#rendering = true;
+        this.#currentSource = this.source;
+        if (!(container instanceof HTMLElement)) {
+            throw new Error('no specified parent.');
+        }
+        this.#parent = container;
+        const grid = document.createElement('div');
+        grid.className = 'grid';
+        grid.setAttribute('tabindex', 0);
+        grid.addEventListener('keydown', e => {
+            let index = this.selectedIndex;
+            let flag = false;
+            if (e.key === 'ArrowUp') {
+                // up
+                flag = true;
+                if (index > 1) {
+                    delete this.#currentSource[index].__selected;
+                    index -= 1;
+                } else {
+                    index = 0;
+                }
+            } else if (e.key === 'ArrowDown') {
+                // down
+                flag = true;
+                const count = this.#currentSource?.length ?? 0;
+                if (index < count - 1) {
+                    delete this.#currentSource[index].__selected;
+                    index += 1;
+                }
+            }
+            if (flag) {
+                this.selectedIndexes = [index];
+                this.scrollToIndex(index);
+                this.#currentSource[index].__selected = true;
+                this.refresh();
+                if (typeof this.selectedRowChanged === 'function') {
+                    this.selectedRowChanged(index);
+                }
+                e.stopPropagation();
+            }
+        });
+        container.replaceChildren(grid);
+        const sizer = document.createElement('span');
+        sizer.className = 'grid-sizer';
+        grid.appendChild(sizer);
+        this.#refs.sizer = sizer;
+
+        // header & body
+        const header = this.#createHeader();
+        grid.appendChild(header);
+        const body = this.#createBody();
+        grid.appendChild(body);
+
+        // loading
+        const loading = document.createElement('div');
+        loading.className = 'grid-loading';
+        loading.appendChild(createIcon('fa-regular', 'spinner-third'));
+        this.#refs.loading = loading;
+        grid.appendChild(loading);
+        this.#el = grid;
+
+        this.#rendering = false;
+        if (this.sortIndex >= 0) {
+            this.sortColumn(true);
+        } else {
+            this.resize();
+        }
+    }
+
+    scrollToIndex(index) {
+        this.#scrollToTop(index * this.rowHeight, true);
+    }
+
+    resize(force) {
+        if (this.#rendering || this.#el == null) {
+            return;
+        }
+        const body = this.#refs.body;
+        let height = this.#refs.header.offsetHeight + 2;
+        let top = body.offsetTop;
+        if (top !== height) {
+            body.style.top = `${height}px`;
+            top = height;
+        }
+
+        height = this.height;
+        if (isNaN(height)) {
+            height = this.#el.offsetHeight - top;
+        } else if (height === 0) {
+            height = this.#refs.bodyContent.offsetHeight;
+            this.#el.style.height = `${top + height}px`;
+        }
+        body.style.height = `${height}px`;
+        const count = truncate((height - 1) / this.rowHeight) * (RedumCount * 2) + 1;
+        if (force || count !== this.#rowCount) {
+            this.#rowCount = count;
+            this.reload();
+        }
+        this.#bodyClientWidth = body.clientWidth;
+    }
+
+    reload() {
+        this.#containerHeight = this.#currentSource.length * this.rowHeight;
+        this.#adjustRows(this.#refs.bodyContent);
+        this.refresh();
+    }
+
+    refresh() {
+        if (this.#refs.bodyContent == null) {
+            throw new Error('body has not been created.');
+        }
+        const rows = this.#refs.bodyContent.children;
+        const widths = {};
+        this.#fillRows(rows, this.columns, widths);
+        if (this.#needResize && widths.flag) {
+            this.#needResize = false;
+            this.columns.forEach((col, i) => {
+                if (!col.autoResize) {
+                    return;
+                }
+                const width = widths[i];
+                if (width > 0) {
+                    this.#changeColumnWidth(i, width);
+                }
+            });
+        }
+    }
+
+    sortColumn(auto, reload) { }
+
+    #createHeader() {
+        const thead = document.createElement('table');
+        thead.className = 'grid-header';
+        const header = document.createElement('tr');
+        thead.appendChild(header);
+        const sizer = this.#refs.sizer;
+        for (let col of this.columns) {
+            if (col.visible === false) {
+                const hidden = document.createElement('th');
+                hidden.style.display = 'none';
+                if (col.sortable === true) {
+                    hidden.dataset.key = col.key;
+                    hidden.addEventListener('mouseup', e => this.#onHeaderClicked(col, e, true));
+                }
+                header.appendChild(hidden);
+                continue;
+            }
+            // style
+            if (col.width > 0 || col.shrink) {
+                col.autoResize = false;
+            } else {
+                col.autoResize = true;
+                this.#needResize = true;
+                sizer.innerText = col.caption;
+                let width = sizer.offsetWidth + 20;
+                if (width < MiniColumnWidth) {
+                    width = MiniColumnWidth;
+                }
+                col.width = width;
+            }
+            col.align ??= 'left';
+            if (col.sortable !== false) {
+                col.sortable = true;
+            }
+            if (col.shrink) {
+                col.style = { 'text-align': col.align };
+            } else {
+                col.style = {
+                    'width': col.width,
+                    'max-width': col.width,
+                    'min-width': col.width,
+                    'text-align': col.align
+                };
+            }
+            // element
+            const th = document.createElement('th');
+            th.dataset.key = col.key;
+            for (let css of Object.entries(col.style)) {
+                th.style.setProperty(css[0], css[1]);
+            }
+            th.style.cursor = col.sortable ? 'pointer' : 'auto';
+            th.addEventListener('mouseup', e => this.#onHeaderClicked(col, e));
+            th.addEventListener('mousedown', e => this.#onDragStart(col, e));
+            const wrapper = document.createElement('div');
+            th.appendChild(wrapper);
+            if (col.enabled !== false && col.allcheck && col.type === Grid.ColumnTypes.Checkbox) {
+                const check = createCheckbox({
+                    onchange: e => this.#onColumnAllChecked(col, e.target.checked)
+                });
+                wrapper.appendChild(check);
+            }
+            const caption = document.createElement('span');
+            caption = col.caption;
+            wrapper.appendChild(caption);
+            // order arrow
+            if (col.sortable) {
+                const arrow = document.createElement('layer');
+                arrow.className = 'arrow';
+                th.appendChild(arrow);
+            }
+            // filter
+            if (col.allowFilter) {
+                // TODO: filter
+            }
+            // resize spliter
+            if (col.resizable !== false) {
+                const spliter = document.createElement('layer');
+                spliter.className = 'spliter';
+                spliter.addEventListener('mousedown', e => this.#onResizeStart(col, e));
+                th.appendChild(spliter);
+            }
+            // tooltip
+            !nullOrEmpty(col.tooltip) && th.setAttribute('title', col.tooltip);
+            header.appendChild(th);
+        }
+        const placeholder = document.createElement('th');
+        const dragger = document.createElement('div');
+        dragger.className = 'dragger';
+        const draggerCursor = document.createElement('layer');
+        draggerCursor.className = 'dragger-cursor';
+        placeholder.append(dragger, draggerCursor);
+        header.appendChild(placeholder);
+
+        sizer.replaceChildren();
+        this.#refs.header = header;
+        this.#refs.dragger = dragger;
+        this.#refs.draggerCursor = draggerCursor;
+        return thead;
+    }
+
+    #createBody() {
+        const body = document.createElement('div');
+        body.className = 'grid-body';
+        body.addEventListener('scroll', e => throttle(this.#onScroll, RefreshInterval, this, e), { passive: true });
+        const cols = this.columns;
+        let height = this.#currentSource.length * this.rowHeight;
+        let width;
+        if (height === 0) {
+            height = 1;
+            width = 0;
+            for (let col of cols) {
+                if (col.visible !== false && !isNaN(col.width)) {
+                    width += col.width + 1;
+                }
+            }
+            width += 1;
+        }
+        this.#containerHeight = height;
+        // body container
+        const bodyContainer = document.createElement('div');
+        bodyContainer.style.position = 'relative';
+        bodyContainer.style.minWidth = '100%';
+        bodyContainer.style.minHeight = '1px';
+        bodyContainer.style.height = `${height}px`;
+        if (width > 0) {
+            bodyContainer.style.width = `${width}px`;
+        }
+        body.appendChild(bodyContainer);
+        // body content
+        const bodyContent = document.createElement('table');
+        bodyContent.className = 'grid-body-content';
+        bodyContainer.appendChild(bodyContent);
+        this.#adjustRows();
+        // events
+        if (!this.holderDisabled) {
+            const holder = document.createElement('div');
+            holder.className = 'grid-hover-holder';
+            holder.style.display = 'none';
+            bodyContainer.appendChild(holder);
+            body.addEventListener('mousemove', e => throttle(this.#onBodyMouseMove, RefreshInterval, this, e, holder));
+        }
+        this.#refs.body = body;
+        this.#refs.bodyContainer = bodyContainer;
+        this.#refs.bodyContent = bodyContent;
+
+        // this.refresh();
+        return body;
+    }
+
+    #adjustRows() {
+        let count = this.#rowCount;
+        if (isNaN(count) || count < 0 || !this.virtual) {
+            count = this.#currentSource.length;
+        }
+        const cols = this.columns;
+        const content = this.#refs.bodyContent;
+        const exists = content.children.length;
+        count -= exists;
+        if (count > 0) {
+            for (let i = 0; i < count; i += 1) {
+                const row = document.createElement('tr');
+                row.className = 'grid-row';
+                row.addEventListener('mousedown', e => this.#onRowClicked(e, exists + 1));
+                row.addEventListener('dblclick', e => this.#onRowDblClicked(e));
+                cols.forEach((col, j) => {
+                    const cell = document.createElement('td');
+                    if (col.visible !== false) {
+                        cell.keyid = ((exists + i) << MaxColumnBit) | j;
+                        if (col.style != null) {
+                            for (let css of Object.entries(col.style)) {
+                                cell.style.setProperty(css[0], css[1]);
+                            }
+                        }
+                        if (col.css != null) {
+                            for (let css of Object.entries(col.css)) {
+                                cell.style.setProperty(css[0], css[1]);
+                            }
+                        }
+                        if (col.type === Grid.ColumnTypes.Checkbox) {
+                            cell.appendChild(GridCheckboxColumn.createEdit(e => this.#onRowChanged(e, exists + i, col, e.target.checked)));
+                        } else if (this.allowHtml && col.type != null && isNaN(col.type)) {
+                            cell.appendChild(col.type.create());
+                        } else {
+                            cell.appendChild(GridColumn.create());
+                        }
+                    }
+                    row.appendChild(cell);
+                });
+                row.appendChild(document.createElement('td'));
+                content.appendChild(row);
+            }
+        } else if (count < 0) {
+            for (let i = -1; i >= count; i -= 1) {
+                // content.removeChild(content.children[exists + i]);
+                content.children[exists + i].remove();
+            }
+        }
+    }
+
+    #fillRows(rows, cols, widths) {
+        const startIndex = this.startIndex;
+        const selected = this.#selectedIndexes;
+        const allowHtml = this.allowHtml;
+        rows.forEach((row, i) => {
+            const vals = this.#currentSource[startIndex + i];
+            if (vals == null) {
+                return;
+            }
+            if (!isPositive(row.children.length)) {
+                return;
+            }
+            const item = vals.values;
+            if (selected.indexOf(startIndex + i) < 0) {
+                row.classList.remove('selected');
+            } else {
+                row.classList.add('selected');
+            }
+            // data
+            const selected = row.dataset.selected === '1';
+            cols.forEach((col, j) => {
+                if (col.visible === false) {
+                    return;
+                }
+                let val;
+                if (col.text != null) {
+                    val = col.text;
+                } else if (typeof col.filter === 'function') {
+                    val = col.filter(item);
+                } else {
+                    val = item[col.key];
+                    if (val?.displayValue != null) {
+                        val = val.displayValue;
+                    }
+                }
+                val ??= '';
+                // fill
+                const cell = row.children[j];
+                const custom = allowHtml && col.type != null && isNaN(col.type);
+                let element;
+                if (vals.__selected ^ selected) {
+                    if (custom) {
+                        element = selected ?
+                            col.type.createEdit(e => this.#onRowChanged(e, startIndex + i, col, col.type.getValue(element))) :
+                            col.type.create();
+                        cell.replaceChildren(element);
+                        // } else if (col.type !== Grid.ColumnTypes.Checkbox) {
+                        //     // TODO:
+                    } else {
+                        element = cell.children[0];
+                    }
+                } else {
+                    element = cell.children[0];
+                }
+                let enabled = col.enabled;
+                if (typeof enabled === 'string') {
+                    enabled = item[enabled];
+                }
+                if (custom) {
+                    col.type.setValue(element, item);
+                    col.type.setEnabled(element, enabled);
+                } else if (col.type === Grid.ColumnTypes.Checkbox) {
+                    GridCheckboxColumn.setValue(element, val);
+                    GridCheckboxColumn.setEnabled(element, enabled);
+                } else {
+                    // TODO: input, dropdown, etc...
+                    GridColumn.setValue(element, val);
+                }
+            })
+        });
+    }
+
+    #changeColumnWidth(i, width) { }
+
+    #scrollToTop(top, reload) { }
+
+    #onHeaderClicked(col, e, force) { }
+    #onDragStart(col, e) { }
+    #onResizeStart(col, e) { }
+    #onColumnAllChecked(col, flag) { }
+    #onScroll(e) { }
+    #onBodyMouseMove(e, holder) { }
+    #onRowClicked(e, index, colIndex) { }
+    #onRowDblClicked(e) { }
+    #onRowChanged(_e, index, col, value) {
+        if (this.#currentSource == null) {
+            return;
+        }
+        const item = this.#currentSource[this.#startIndex + index].values;
+        if (item == null) {
+            return;
+        }
+        const enabled = typeof col.enabled === 'string' ? item[col.enabled] : col.enabled;
+        if (enabled !== false) {
+            item[col.key] = value;
+            item.__changed = true;
+            if (typeof col.onchanged === 'function') {
+                col.onchanged.call(this, item, value);
+            }
+        }
+    }
+}
+
+export default Grid;
\ No newline at end of file
diff --git a/lib/ui/tooltip.js b/lib/ui/tooltip.js
index e0fce9d..0a4ac06 100644
--- a/lib/ui/tooltip.js
+++ b/lib/ui/tooltip.js
@@ -48,8 +48,7 @@ function setTooltip(container, content) {
     });
 }
 
-function resolveTooltip(container) {
-    container ??= document.body;
+function resolveTooltip(container = document.body) {
     const tips = container.querySelectorAll('[title]');
     for (let tip of tips) {
         const title = tip.getAttribute('title');
diff --git a/lib/utility.js b/lib/utility.js
index c3e8c1b..24de190 100644
--- a/lib/utility.js
+++ b/lib/utility.js
@@ -9,6 +9,28 @@ function isPositive(n) {
     return !isNaN(n) && n > 0;
 }
 
+function isMobile() {
+    return /mobile/i.test(navigator.userAgent);
+}
+
+function throttle(method, delay = 100, context = g, ...args) {
+    if (method == null) {
+        return;
+    }
+    method.tiid && clearTimeout(method.tiid);
+    const current = new Date();
+    if (method.tdate == null || current - method.tdate > delay) {
+        method.apply(context, args);
+        method.tdate = current;
+    } else {
+        method.tiid = setTimeout(() => method.apply(context, args), delay);
+    }
+}
+
+function truncate(v) {
+    return (v > 0 ? Math.floor : Math.ceil)(v);
+}
+
 export {
     // cookie
     getCookie,
@@ -29,5 +51,9 @@ export {
     padStart,
     // variables
     g as global,
-    isPositive
+    isPositive,
+    isMobile,
+    // functions
+    throttle,
+    truncate
 }
\ No newline at end of file
diff --git a/lib/utility/lgres.js b/lib/utility/lgres.js
index 962b78f..4019bf9 100644
--- a/lib/utility/lgres.js
+++ b/lib/utility/lgres.js
@@ -45,8 +45,7 @@ function getStorageKey(lgid) {
     return `res_${lgid}`;
 }
 
-async function doRefreshLgres(template) {
-    template ??= '';
+async function doRefreshLgres(template = '') {
     const lgid = getCurrentLgId();
     const r = await get(`language/${lgid}${template}`);
     const dict = await r.json();
@@ -81,7 +80,6 @@ function getLanguage(lgres, key, defaultValue) {
 }
 
 function applyLanguage(dom, result) {
-    dom ??= document.body;
     for (let text of dom.querySelectorAll('[data-lgid]')) {
         const key = text.dataset.lgid;
         if (text.tagName === 'INPUT') {
@@ -100,8 +98,7 @@ function applyLanguage(dom, result) {
     }
 }
 
-async function init(dom, options) {
-    options ??= {};
+async function init(dom = document.body, options = {}) {
     const lgid = getCurrentLgId();
     let lgres = localStorage.getItem(getStorageKey(lgid));
     let result;
diff --git a/lib/utility/request.js b/lib/utility/request.js
index eaa508c..1d1d6ba 100644
--- a/lib/utility/request.js
+++ b/lib/utility/request.js
@@ -8,8 +8,7 @@ function combineUrl(url) {
     return (consts.path || '') + url;
 }
 
-function get(url, options) {
-    options ??= {};
+function get(url, options = {}) {
     return fetch(combineUrl(url), {
         method: options.method || 'GET',
         headers: {
@@ -21,8 +20,7 @@ function get(url, options) {
     });
 }
 
-function post(url, data, options) {
-    options ??= {};
+function post(url, data, options = {}) {
     // let contentType;
     if (data instanceof FormData) {
         // contentType = 'multipart/form-data';
@@ -47,7 +45,7 @@ function post(url, data, options) {
     });
 }
 
-function upload(url, data, options) {
+function upload(url, data, options = {}) {
     return new Promise((resolve, reject) => {
         const request = new XMLHttpRequest();
         request.onreadystatechange = function () {
@@ -59,7 +57,6 @@ function upload(url, data, options) {
                 }
             }
         };
-        options ??= {};
         if (typeof options.progress === 'function') {
             request.upload.addEventListener('progress', function (ev) {
                 if (ev.lengthComputable) {