fix: 🐛 Always show vertical scrollbar

Decouple bodyScrollable from header. Now header position is synced based
on scrollLeft of bodyScrollable. Also, remove redundant .dt-body
container.

src/body-renderer.js

@@ -1,5 +1,4 @@
 import HyperList from 'hyperlist';
-import $ from './dom';
 
 export default class BodyRenderer {
     constructor(instance) {
@@ -9,7 +8,6 @@ export default class BodyRenderer {
         this.rowmanager = instance.rowmanager;
         this.cellmanager = instance.cellmanager;
         this.bodyScrollable = instance.bodyScrollable;
-        this.bodyDiv = $('.dt-body', this.bodyScrollable);
         this.footer = this.instance.footer;
         this.log = instance.log;
     }
@@ -39,9 +37,9 @@ export default class BodyRenderer {
         };
 
         if (!this.hyperlist) {
-            this.hyperlist = new HyperList(this.bodyDiv, config);
+            this.hyperlist = new HyperList(this.bodyScrollable, config);
         } else {
-            this.hyperlist.refresh(this.bodyDiv, config);
+            this.hyperlist.refresh(this.bodyScrollable, config);
         }
 
         this.renderFooter();
@@ -113,16 +111,6 @@ export default class BodyRenderer {
         this.instance.toastMessage.innerHTML = '';
     }
 
-    getBodyHTML(rows) {
-        return `
-            <div class="dt-body">
-                <div>
-                    ${rows.map(row => this.rowmanager.getRowHTML(row, row.meta)).join('')}
-                </div>
-            </div>
-        `;
-    }
-
     getNoDataHTML() {
         return `<div class="dt-scrollable__no-data">${this.options.noDataMessage}</div>`;
     }

src/datatable.js

@@ -69,13 +69,9 @@ class DataTable {
     prepareDom() {
         this.wrapper.innerHTML = `
             <div class="datatable">
-                <div class="dt-header">
-                </div>
-                <div class="dt-scrollable">
-                    <div class="dt-body"></div>
-                </div>
-                <div class="dt-footer">
-                </div>
+                <div class="dt-header"></div>
+                <div class="dt-scrollable"></div>
+                <div class="dt-footer"></div>
                 <div class="dt-freeze">
                     <span class="dt-freeze__message">
                         ${this.options.freezeMessage}

src/style.css

@@ -26,25 +26,17 @@
 
 .datatable {
     position: relative;
-    overflow: auto;
+    overflow: hidden;
 }
 
 .dt-header {
     border-collapse: collapse;
-    border-bottom: 1px solid var(--dt-border-color);
-
-    position: absolute;
-    top: 0;
-    left: 0;
-}
-
-.dt-body {
-    border-collapse: collapse;
 }
 
 .dt-scrollable {
     height: 40vw;
     overflow: auto;
+    border-top: 1px solid var(--dt-border-color);
 
     &--highlight-all {
         background-color: var(--dt-selection-highlight-color);

src/style.js

@@ -23,6 +23,7 @@ export default class Style {
         this.styleEl = styleEl;
 
         this.bindResizeWindow();
+        this.bindScrollHeader();
     }
 
     get stylesheet() {
@@ -38,10 +39,27 @@ export default class Style {
         }
     }
 
+    bindScrollHeader() {
+        this._settingHeaderPosition = false;
+
+        $.on(this.bodyScrollable, 'scroll', (e) => {
+            if (this._settingHeaderPosition) return;
+
+            this._settingHeaderPosition = true;
+
+            requestAnimationFrame(() => {
+                const scrollLeft = e.target.scrollLeft;
+                $.style(this.header, {
+                    transform: `translateX(-${scrollLeft}px)`
+                });
+                this._settingHeaderPosition = false;
+            });
+        });
+    }
+
     onWindowResize() {
         this.distributeRemainingWidth();
         this.refreshColumnWidth();
-        this.compensateScrollbarWidth();
         this.setBodyStyle();
     }
 
@@ -124,7 +142,6 @@ export default class Style {
         this.setupColumnWidth();
         this.distributeRemainingWidth();
         this.setColumnStyle();
-        this.compensateScrollbarWidth();
         this.setBodyStyle();
     }
 
@@ -224,22 +241,13 @@ export default class Style {
         }
     }
 
-    compensateScrollbarWidth() {
-        if (!$.hasVerticalOverflow($('.dt-body', this.bodyScrollable))) return;
-
-        const scrollbarWidth = $.scrollbarWidth();
-        const lastCol = this.datamanager.getColumn(-1);
-        const width = lastCol.width - scrollbarWidth;
-        this.columnmanager.setColumnWidth(lastCol.colIndex, width);
-    }
-
     distributeRemainingWidth() {
         if (this.options.layout !== 'fluid') return;
 
         const wrapperWidth = $.style(this.instance.datatableWrapper, 'width');
-        const headerWidth = $.style(this.header, 'width');
+        const firstRowWidth = $.style($('.dt-row', this.bodyScrollable), 'width');
         const resizableColumns = this.datamanager.getColumns().filter(col => col.resizable);
-        const deltaWidth = (wrapperWidth - headerWidth) / resizableColumns.length;
+        const deltaWidth = (wrapperWidth - firstRowWidth) / resizableColumns.length;
 
         resizableColumns.map(col => {
             const width = $.style(this.getColumnHeaderElement(col.colIndex), 'width');
@@ -281,8 +289,11 @@ export default class Style {
     }
 
     setBodyStyle() {
-        const width = $.style(this.header, 'width');
+        const bodyWidth = $.style(this.datatableWrapper, 'width');
+        const firstRow = $('.dt-row', this.bodyScrollable);
+        const rowWidth = $.style(firstRow, 'width');
 
+        let width = bodyWidth > rowWidth ? rowWidth : bodyWidth;
         $.style(this.bodyScrollable, {
             width: width + 'px'
         });
@@ -300,9 +311,11 @@ export default class Style {
             });
         }
 
-        $.style(this.bodyScrollable, {
-            marginTop: $.style(this.header, 'height') + 'px'
-        });
+        if (this.options.layout === 'fluid') {
+            $.style(this.bodyScrollable, {
+                overflowX: 'hidden'
+            });
+        }
     }
 
     getColumnHeaderElement(colIndex) {