Light refactoring with Array.at()

Author: J-Fields

extensionBase.ts

@@ -111,9 +111,10 @@ export async function activate(context: vscode.ExtensionContext, handleLocal: bo
   Register.loadFromDisk(handleLocal);
   await Promise.all([ExCommandLine.loadHistory(context), SearchCommandLine.loadHistory(context)]);
 
-  if (vscode.window.activeTextEditor) {
-    const filepathComponents = vscode.window.activeTextEditor.document.fileName.split(/\\|\//);
-    Register.setReadonlyRegister('%', filepathComponents[filepathComponents.length - 1]);
+  const document = vscode.window.activeTextEditor?.document;
+  if (document) {
+    const filepathComponents = document.fileName.split(/\\|\//);
+    Register.setReadonlyRegister('%', filepathComponents.at(-1)!);
   }
 
   // workspace events
@@ -192,10 +193,9 @@ export async function activate(context: vscode.ExtensionContext, handleLocal: bo
         if (modeHandler == null) {
           shouldDelete = true;
         } else {
-          const document = modeHandler.vimState.document;
-          if (!vscode.workspace.textDocuments.includes(document)) {
+          if (!vscode.workspace.textDocuments.includes(modeHandler.vimState.document)) {
             shouldDelete = true;
-            if (closedDocument === document) {
+            if (closedDocument === modeHandler.vimState.document) {
               lastClosedModeHandler = modeHandler;
             }
           }

src/actions/commands/insert.ts

@@ -235,7 +235,7 @@ export class CommandInsertInInsertMode extends BaseCommand {
   keys = ['<character>'];
 
   public override async exec(position: Position, vimState: VimState): Promise<void> {
-    const char = this.keysPressed[this.keysPressed.length - 1];
+    const char = this.keysPressed.at(-1)!;
 
     let text = char;
 
@@ -271,7 +271,7 @@ export class CommandInsertInInsertMode extends BaseCommand {
   }
 
   public override toString(): string {
-    return this.keysPressed[this.keysPressed.length - 1];
+    return this.keysPressed.at(-1)!;
   }
 }
 

src/actions/operator.ts

@@ -55,7 +55,7 @@ export abstract class BaseOperator extends BaseAction {
 
   public doesRepeatedOperatorApply(vimState: VimState, keysPressed: string[]) {
     const nonCountActions = vimState.recordedState.actionsRun.filter((x) => x.name !== 'cmd_num');
-    const prevAction = nonCountActions[nonCountActions.length - 1];
+    const prevAction = nonCountActions.at(-1);
     return (
       keysPressed.length === 1 &&
       prevAction &&
@@ -894,7 +894,7 @@ class ActionVisualReflowParagraph extends BaseOperator {
     const chunksToReflow: Chunk[] = [];
 
     for (const line of s.split('\n')) {
-      let lastChunk: Chunk | undefined = chunksToReflow[chunksToReflow.length - 1];
+      let lastChunk: Chunk | undefined = chunksToReflow.at(-1);
       const trimmedLine = line.trimStart();
 
       // See what comment type they are using.
@@ -958,7 +958,7 @@ class ActionVisualReflowParagraph extends BaseOperator {
 
       // Parse out commenting style, gather words.
 
-      lastChunk = chunksToReflow[chunksToReflow.length - 1];
+      lastChunk = chunksToReflow.at(-1)!;
 
       if (lastChunk.commentType.singleLine) {
         // is it a continuation of a comment like "//"
@@ -1001,7 +1001,7 @@ class ActionVisualReflowParagraph extends BaseOperator {
         // Preserve blank lines in output.
         if (line.trim() === '') {
           // Replace empty content line with blank line.
-          if (lines[lines.length - 1] === '') {
+          if (lines.at(-1) === '') {
             lines.pop();
           }
 
@@ -1015,7 +1015,7 @@ class ActionVisualReflowParagraph extends BaseOperator {
 
         // Repeatedly partition line into pieces that fit in maximumLineLength
         while (line) {
-          const lastLine = lines[lines.length - 1];
+          const lastLine = lines.at(-1)!;
 
           // Determine the separator that we'd need to add to the last line
           // in order to join onto this line.
@@ -1078,7 +1078,7 @@ class ActionVisualReflowParagraph extends BaseOperator {
       }
 
       // Drop final empty content line.
-      if (lines[lines.length - 1] === '') {
+      if (lines.at(-1) === '') {
         lines.pop();
       }
 

src/cmd_line/commandLine.ts

@@ -359,11 +359,7 @@ export class SearchCommandLine extends CommandLine {
   }
 
   public static async addSearchStateToHistory(searchState: SearchState) {
-    const prevSearchString =
-      SearchCommandLine.previousSearchStates.length === 0
-        ? undefined
-        : SearchCommandLine.previousSearchStates[SearchCommandLine.previousSearchStates.length - 1]
-            .searchString;
+    const prevSearchString = SearchCommandLine.previousSearchStates.at(-1)?.searchString;
     // Store this search if different than previous
     if (searchState.searchString !== prevSearchString) {
       SearchCommandLine.previousSearchStates.push(searchState);
@@ -467,11 +463,9 @@ export class SearchCommandLine extends CommandLine {
   public async run(vimState: VimState): Promise<void> {
     // Repeat the previous search if no new string is entered
     if (this.text === '') {
-      if (SearchCommandLine.previousSearchStates.length > 0) {
-        this.text =
-          SearchCommandLine.previousSearchStates[
-            SearchCommandLine.previousSearchStates.length - 1
-          ].searchString;
+      const prevSearchString = SearchCommandLine.previousSearchStates.at(-1)?.searchString;
+      if (prevSearchString !== undefined) {
+        this.text = prevSearchString;
       }
     }
     Logger.info(`Searching for ${this.text}`);
@@ -509,10 +503,7 @@ export class SearchCommandLine extends CommandLine {
   public async escape(vimState: VimState): Promise<void> {
     vimState.cursorStopPosition = this.searchState.cursorStartPosition;
 
-    const prevSearchList = SearchCommandLine.previousSearchStates;
-    globalState.searchState = prevSearchList
-      ? prevSearchList[prevSearchList.length - 1]
-      : undefined;
+    globalState.searchState = SearchCommandLine.previousSearchStates.at(-1);
 
     if (vimState.modeData.mode === Mode.SearchInProgressMode) {
       const offset =

src/cmd_line/commands/move.ts

@@ -60,14 +60,11 @@ export class MoveCommand extends ExCommand {
     let cursorPosition: Position;
     if (dest > sourceEnd) {
       // make the cursor position at the beginning of the endline.
-      cursorPosition = new Position(
-        Math.max(dest, 0),
-        lines[lines.length - 1].match(/\S/)?.index ?? 0,
-      );
+      cursorPosition = new Position(Math.max(dest, 0), lines.at(-1)!.match(/\S/)?.index ?? 0);
     } else {
       cursorPosition = new Position(
         Math.max(dest + lines.length, 0),
-        lines[lines.length - 1].match(/\S/)?.index ?? 0,
+        lines.at(-1)!.match(/\S/)?.index ?? 0,
       );
     }
     // delete

src/common/motion/position.ts

@@ -511,10 +511,7 @@ Position.prototype.advancePositionByText = function (this: Position, text: strin
   if (newlines.length === 0) {
     return new Position(this.line, this.character + text.length);
   } else {
-    return new Position(
-      this.line + newlines.length,
-      text.length - (newlines[newlines.length - 1] + 1),
-    );
+    return new Position(this.line + newlines.length, text.length - (newlines.at(-1)! + 1));
   }
 };
 

src/configuration/remapper.ts

@@ -111,7 +111,7 @@ export class Remapper implements IRemapper {
 
     const userDefinedRemappings = configuration[this.configKey] as Map<string, IKeyRemapping>;
 
-    if (keys[keys.length - 1] === SpecialKeys.TimeoutFinished) {
+    if (keys.at(-1) === SpecialKeys.TimeoutFinished) {
       // Timeout finished. Don't let an ambiguous or potential remap start another timeout again
       keys = keys.slice(0, keys.length - 1);
       allowBufferingKeys = false;
@@ -422,7 +422,7 @@ export class Remapper implements IRemapper {
             // If there was a performing remap that finished waiting for timeout then only the remaining keys
             // that are not part of that remap were typed by the user.
             let specialKey: string | undefined = '';
-            if (remainingKeys[remainingKeys.length - 1] === SpecialKeys.TimeoutFinished) {
+            if (remainingKeys.at(-1) === SpecialKeys.TimeoutFinished) {
               specialKey = remainingKeys.pop();
             }
             const lastRemap = remapState.wasPerformingRemapThatFinishedWaitingForTimeout.after!;

src/mode/modeHandler.ts

@@ -513,10 +513,7 @@ export class ModeHandler implements vscode.Disposable, IModeHandler {
       // is disabled. This makes it possible to map zero without making it impossible
       // to type a count with a zero.
       const preventZeroRemap =
-        key === '0' &&
-        this.vimState.recordedState.actionsRun[
-          this.vimState.recordedState.actionsRun.length - 1
-        ] instanceof CommandNumber;
+        key === '0' && this.vimState.recordedState.actionsRun.at(-1) instanceof CommandNumber;
 
       // Check for remapped keys if:
       // 1. We are not currently performing a non-recursive remapping
@@ -544,10 +541,7 @@ export class ModeHandler implements vscode.Disposable, IModeHandler {
           // Remove the <TimeoutFinished> key and get the key before that. If the <TimeoutFinished>
           // key was the last key, then 'key' will be undefined and won't be sent to handle action.
           this.vimState.recordedState.commandList.pop();
-          key =
-            this.vimState.recordedState.commandList[
-              this.vimState.recordedState.commandList.length - 1
-            ];
+          key = this.vimState.recordedState.commandList.at(-1)!;
         }
         if (key !== undefined) {
           handledAsAction = await this.handleKeyAsAnAction(key);
@@ -684,11 +678,10 @@ export class ModeHandler implements vscode.Disposable, IModeHandler {
     recordedState.actionsRunPressedKeys.push(...recordedState.actionKeys);
 
     let actionToRecord: BaseAction | undefined = action;
-    if (recordedState.actionsRun.length === 0) {
+    const lastAction = recordedState.actionsRun.at(-1);
+    if (lastAction === undefined) {
       recordedState.actionsRun.push(action);
     } else {
-      const lastAction = recordedState.actionsRun[recordedState.actionsRun.length - 1];
-
       const actionCanBeMergedWithDocumentChange =
         action instanceof CommandInsertInInsertMode ||
         action instanceof CommandBackspaceInInsertMode ||
@@ -1420,7 +1413,7 @@ export class ModeHandler implements vscode.Disposable, IModeHandler {
         const combinedSelections: vscode.Selection[] = [];
         sel.forEach((s, i) => {
           if (i > 0) {
-            const previousSelection = combinedSelections[combinedSelections.length - 1];
+            const previousSelection = combinedSelections.at(-1)!;
             const overlap = s.intersection(previousSelection);
             if (overlap) {
               combinedSelections[combinedSelections.length - 1] = s.anchor.isBeforeOrEqual(s.active)
@@ -1498,13 +1491,11 @@ export class ModeHandler implements vscode.Disposable, IModeHandler {
        * Extend this condition if it is the desired behaviour for other actions as well.
        */
       const isLastCursorTracked =
-        this.vimState.recordedState.actionsRun[
-          this.vimState.recordedState.actionsRun.length - 1
-        ] instanceof ActionOverrideCmdD;
+        this.vimState.recordedState.actionsRun.at(-1) instanceof ActionOverrideCmdD;
 
       let cursorToTrack: Cursor;
       if (isLastCursorTracked) {
-        cursorToTrack = this.vimState.cursors[this.vimState.cursors.length - 1];
+        cursorToTrack = this.vimState.cursors.at(-1)!;
       } else {
         cursorToTrack = this.vimState.cursors[0];
       }
@@ -1585,13 +1576,9 @@ export class ModeHandler implements vscode.Disposable, IModeHandler {
     if (this.vimState.currentMode === Mode.Insert || this.vimState.currentMode === Mode.Replace) {
       let virtualKey: string | undefined;
       if (this.vimState.recordedState.bufferedKeys.length > 0) {
-        virtualKey =
-          this.vimState.recordedState.bufferedKeys[
-            this.vimState.recordedState.bufferedKeys.length - 1
-          ];
+        virtualKey = this.vimState.recordedState.bufferedKeys.at(-1);
       } else if (this.vimState.recordedState.waitingForAnotherActionKey) {
-        virtualKey =
-          this.vimState.recordedState.actionKeys[this.vimState.recordedState.actionKeys.length - 1];
+        virtualKey = this.vimState.recordedState.actionKeys.at(-1);
         if (virtualKey === '<C-r>') {
           virtualKey = '"';
         } else if (virtualKey === '<C-k>') {

src/textobject/word.ts

@@ -158,7 +158,7 @@ export function prevWordEnd(document: TextDocument, pos: Position, wordType: Wor
       if (currentLine > -1) {
         continue;
       }
-      newCharacter = positions[positions.length - 1];
+      newCharacter = positions.at(-1)!;
     } else {
       newCharacter = positions[index];
     }

src/vimscript/expression/evaluate.ts

@@ -268,7 +268,7 @@ export class EvaluationContext {
 
     let store: VariableStore | undefined;
     if (this.localScopes.length > 0 && varExpr.namespace === undefined) {
-      store = this.localScopes[this.localScopes.length - 1];
+      store = this.localScopes.at(-1);
     } else if (varExpr.namespace === 'g' || varExpr.namespace === undefined) {
       store = EvaluationContext.globalVariables;
     } else {
@@ -1174,7 +1174,7 @@ export class EvaluationContext {
           if (result[0] === '') {
             result.shift();
           }
-          if (result && result[result.length - 1] === '') {
+          if (result.at(-1) === '') {
             result.pop();
           }
         }