feat: boost keyword suggestions in some locations, adds extends in type contexts

Author: zardoy

typescript/src/completions/boostKeywordSuggestions.ts

@@ -0,0 +1,29 @@
+import { findChildContainingPosition } from '../utils'
+
+export default (entries: ts.CompletionEntry[], position: number, node: ts.Node): ts.CompletionEntry[] | undefined => {
+    // todo-not-sure for now, requires explicit completion trigger
+    const prevCharIsSpace = node.getSourceFile().getFullText()[position - 1] === ' '
+    if (!prevCharIsSpace) return
+    let extendsKeyword = ts.isInterfaceDeclaration(node) && node.end === position - 1
+    const addOrBoostKeywords = [] as string[]
+    if (!extendsKeyword) {
+        const leftNode = findChildContainingPosition(ts, node.getSourceFile(), position - 2)
+        if (leftNode && ts.isIdentifier(leftNode) && ts.isTypeParameterDeclaration(leftNode.parent)) {
+            if (!leftNode.parent.constraint) extendsKeyword = true
+        } else if (leftNode) {
+            if (ts.isBlock(leftNode)) {
+                if (ts.isTryStatement(leftNode.parent) && leftNode.parent.tryBlock === leftNode) addOrBoostKeywords.push(...['catch', 'finally'])
+                else if (ts.isCatchClause(leftNode.parent) && leftNode.parent.block === leftNode) addOrBoostKeywords.push('finally')
+            }
+            if (leftNode.kind === ts.SyntaxKind.ExportKeyword) {
+                addOrBoostKeywords.push(...['const', 'function', 'default', 'from', 'let'])
+            }
+        }
+    }
+    if (extendsKeyword) addOrBoostKeywords.push('extends')
+    if (addOrBoostKeywords.length === 0) return
+    return [
+        ...addOrBoostKeywords.map(keyword => ({ name: keyword, kind: ts.ScriptElementKind.keyword, sortText: '07' })),
+        ...entries.filter(({ name }) => !addOrBoostKeywords.includes(name)),
+    ]
+}

typescript/src/completionsAtPosition.ts

@@ -13,6 +13,7 @@ import prepareTextForEmmet from './specialCommands/prepareTextForEmmet'
 import objectLiteralHelpers from './completions/objectLiteralHelpers'
 import switchCaseExcludeCovered from './completions/switchCaseExcludeCovered'
 import additionalTypesSuggestions from './completions/additionalTypesSuggestions'
+import boostKeywordSuggestions from './completions/boostKeywordSuggestions'
 
 export type PrevCompletionMap = Record<string, { originalName?: string; documentationOverride?: string | ts.SymbolDisplayPart[] }>
 
@@ -100,6 +101,7 @@ export const getCompletionsAtPosition = (
     if (!prior) return
 
     if (c('fixSuggestionsSorting')) prior.entries = fixPropertiesSorting(prior.entries, leftNode, sourceFile, program) ?? prior.entries
+    if (node) prior.entries = boostKeywordSuggestions(prior.entries, position, node) ?? prior.entries
 
     const entryNames = new Set(prior.entries.map(({ name }) => name))
     if (c('removeUselessFunctionProps.enable')) prior.entries = prior.entries.filter(e => !['Symbol', 'caller', 'prototype'].includes(e.name))