package upgrades & linter fixes

src/browser/CoreBrowserTerminal.ts

@@ -212,7 +212,7 @@ export class CoreBrowserTerminal extends CoreTerminal implements ITerminal {
     if (!this._themeService) return;
     for (const req of event) {
       let acc: 'foreground' | 'background' | 'cursor' | 'ansi';
-      let ident = '';
+      let ident: string;
       switch (req.index) {
         case SpecialColorIndex.FOREGROUND: // OSC 10 | 110
           acc = 'foreground';

src/browser/Terminal2.test.ts

@@ -125,7 +125,7 @@ function formatError(input: string, output: string, expected: string): string {
 // simple debug output of terminal cells
 function terminalToString(term: CoreBrowserTerminal): string {
   let result = '';
-  let lineText = '';
+  let lineText: string;
   for (let line = term.buffer.ybase; line < term.buffer.ybase + term.rows; line++) {
     lineText = term.buffer.lines.get(line)!.translateToString(true);
     // rtrim empty cells as xterm does

src/browser/renderer/dom/DomRendererRowFactory.ts

@@ -90,14 +90,14 @@ export class DomRendererRowFactory {
     let charElement: HTMLSpanElement | undefined;
     let cellAmount = 0;
     let text = '';
-    let i = 0;
+    let i;
     let oldBg = 0;
     let oldFg = 0;
     let oldExt = 0;
     let oldLinkHover: number | boolean = false;
     let oldSpacing = 0;
     let oldIsInSelection: boolean = false;
-    let spacing = 0;
+    let spacing;
     let skipJoinedCheckUntilX = 0;
     const classes: string[] = [];
 
@@ -231,6 +231,7 @@ export class DomRendererRowFactory {
           }
           charElement = this._document.createElement('span');
           cellAmount = 0;
+          // eslint-disable-next-line no-useless-assignment
           text = '';
         }
       }

src/browser/renderer/dom/WidthCache.ts

@@ -110,7 +110,7 @@ export class WidthCache implements IDisposable {
    * `variant` denotes the font variant to be used.
    */
   public get(c: string, bold: boolean | number, italic: boolean | number): number {
-    let cp = 0;
+    let cp: number;
     if (!bold && !italic && c.length === 1 && (cp = c.charCodeAt(0)) < WidthCacheSettings.FLAT_SIZE) {
       if (this._flat[cp] !== WidthCacheSettings.FLAT_UNSET) {
         return this._flat[cp];

src/browser/scrollable/touch.ts

@@ -367,7 +367,7 @@ export class Gesture extends Disposable {
   private _dispatchEvent(event: IGestureEvent): void {
     if (event.type === EventType.TAP) {
       const currentTime = (new Date()).getTime();
-      let setTapCount = 0;
+      let setTapCount;
       if (currentTime - this._lastSetTapCountTime > Gesture._clearTapCountTime) {
         setTapCount = 1;
       } else {

src/browser/services/CharacterJoinerService.test.ts

@@ -285,7 +285,7 @@ function substringJoiner(substring: string): (sequence: string) => [number, numb
   return (sequence: string): [number, number][] => {
     const ranges: [number, number][] = [];
     let searchIndex = 0;
-    let matchIndex = -1;
+    let matchIndex;
 
     while ((matchIndex = sequence.indexOf(substring, searchIndex)) !== -1) {
       const matchEndIndex = matchIndex + substring.length;

src/browser/services/SelectionService.ts

@@ -919,10 +919,10 @@ export class SelectionService extends Disposable implements ISelectionService {
     // Calculate the start _column_, converting the the string indexes back to
     // column coordinates.
     let start =
-        startIndex // The index of the selection's start char in the line string
-        + charOffset // The difference between the initial char's column and index
-        - leftWideCharCount // The number of wide chars left of the initial char
-        + leftLongCharOffset; // The number of additional chars left of the initial char added by columns with strings longer than 1 (emojis)
+      startIndex // The index of the selection's start char in the line string
+      + charOffset // The difference between the initial char's column and index
+      - leftWideCharCount // The number of wide chars left of the initial char
+      + leftLongCharOffset; // The number of additional chars left of the initial char added by columns with strings longer than 1 (emojis)
 
     // Calculate the length in _columns_, converting the the string indexes back
     // to column coordinates.

src/common/TaskQueue.ts

@@ -74,10 +74,10 @@ abstract class TaskQueue implements ITaskQueue {
 
   private _process(deadline: ITaskDeadline): void {
     this._idleCallback = undefined;
-    let taskDuration = 0;
+    let taskDuration: number;
     let longestTask = 0;
     let lastDeadlineRemaining = deadline.timeRemaining();
-    let deadlineRemaining = 0;
+    let deadlineRemaining: number;
     while (this._i < this._tasks.length) {
       taskDuration = performance.now();
       if (!this._tasks[this._i]()) {

src/common/data/Charsets.ts

@@ -98,8 +98,7 @@ CHARSETS['4'] = {
  * ESC (C or ESC (5
  * Reference: http://vt100.net/docs/vt220-rm/table2-7.html
  */
-CHARSETS['C'] =
-CHARSETS['5'] = {
+CHARSETS['C'] = CHARSETS['5'] = {
   '[': 'Ä',
   '\\': 'Ö',
   ']': 'Å',
@@ -185,8 +184,7 @@ CHARSETS['Y'] = {
  * ESC (E or ESC (6
  * Reference: http://vt100.net/docs/vt220-rm/table2-12.html
  */
-CHARSETS['E'] =
-CHARSETS['6'] = {
+CHARSETS['E'] = CHARSETS['6'] = {
   '@': 'Ä',
   '[': 'Æ',
   '\\': 'Ø',
@@ -220,8 +218,7 @@ CHARSETS['Z'] = {
  * ESC (H or ESC (7
  * Reference: http://vt100.net/docs/vt220-rm/table2-14.html
  */
-CHARSETS['H'] =
-CHARSETS['7'] = {
+CHARSETS['H'] = CHARSETS['7'] = {
   '@': 'É',
   '[': 'Ä',
   '\\': 'Ö',

src/common/input/TextDecoder.ts

@@ -148,7 +148,7 @@ export class Utf8ToUtf32 {
     let byte2: number;
     let byte3: number;
     let byte4: number;
-    let codepoint = 0;
+    let codepoint;
     let startPos = 0;
 
     // handle leftover bytes

src/common/parser/EscapeSequenceParser.ts

@@ -572,8 +572,8 @@ export class EscapeSequenceParser extends Disposable implements IEscapeSequenceP
    * ```
    */
   public parse(data: Uint32Array, length: number, promiseResult?: boolean): void | Promise<boolean> {
-    let code = 0;
-    let transition = 0;
+    let code: number;
+    let transition: number;
     let start = 0;
     let handlerResult: void | boolean | Promise<boolean>;
 

src/common/services/DecorationService.ts

@@ -72,10 +72,10 @@ export class DecorationService extends Disposable implements IDecorationService
   }
 
   public *getDecorationsAtCell(x: number, line: number, layer?: 'bottom' | 'top'): IterableIterator<IInternalDecoration> {
-    let xmin = 0;
-    let xmax = 0;
-    let ymin = 0;
-    let ymax = 0;
+    let xmin;
+    let xmax;
+    let ymin;
+    let ymax;
     for (const d of this._decorations.values()) {
       ymin = d.marker.line;
       ymax = ymin + (d.options.height ?? 1);

src/tsconfig-library-base.json

@@ -4,7 +4,6 @@
     "composite": true,
     "strict": true,
     "declarationMap": true,
-    "experimentalDecorators": true,
-    "downlevelIteration": true
+    "experimentalDecorators": true
   }
 }