feat(vscode): support mapped types

packages/api/src/tree.ts

@@ -206,12 +206,17 @@ function _generateTypeTree({ symbol, type }: SymbolOrType, ctx: TypeTreeContext,
 
     function getIndexInfo(indexInfo: TSIndexInfoMerged): IndexInfo {
         const { typeChecker } = ctx
+
+        const parameterSymbol =
+            // @ts-expect-error
+            indexInfo?.declaration?.parameters?.[0]?.symbol
+         ?? indexInfo?.parameterType?.getSymbol()
 
         return {
             ...indexInfo.keyType && { keyType: parseType(indexInfo.keyType) },
             ...indexInfo.type && { type: parseType(indexInfo.type) },
-            // @ts-expect-error
-            parameterSymbol: wrapSafe(getSymbolInfo)(wrapSafe(typeChecker.getSymbolAtLocation)(indexInfo?.declaration?.parameters?.[0]))
+            // parameterSymbol: wrapSafe(getSymbolInfo)(wrapSafe(typeChecker.getSymbolAtLocation)(indexInfo?.declaration?.parameters?.[0]))
+            parameterSymbol: wrapSafe(getSymbolInfo)(parameterSymbol),
         }
     }
 

packages/api/src/types.ts

@@ -11,6 +11,7 @@ export type IndexInfo = {
     keyType?: TypeInfo,
     type?: TypeInfo,
     parameterSymbol?: SymbolInfo
+    // parameterName?: string
 }
 
 // export type FunctionParameterInfo = {

packages/api/src/util.ts

@@ -98,7 +98,7 @@ interface MappedType extends ts.Type {
 export function getIndexInfos(typeChecker: ts.TypeChecker, type: ts.Type) {
     const indexInfos: TSIndexInfoMerged[] = [ ...typeChecker.getIndexInfosOfType(type) ]
 
-    if((type.flags & ts.TypeFlags.Object) && ((type as ObjectType).objectFlags & ts.ObjectFlags.Mapped) && !((type as ObjectType).objectFlags & ts.ObjectFlags.Instantiated)) {
+    if(indexInfos.length === 0 && (type.flags & ts.TypeFlags.Object) && ((type as ObjectType).objectFlags & ts.ObjectFlags.Mapped) && !((type as ObjectType).objectFlags & ts.ObjectFlags.Instantiated)) {
         const mappedType = type as MappedType
 
         if(mappedType.typeParameter) {

packages/typescript-explorer/src/localization.ts

@@ -25,7 +25,7 @@ export const KindText: Record<Kind, string> = {
     "enum_literal": "$1",
     "number_literal": "$1",
     "conditional": "conditional",
-    "index": "Index",
+    "index": "keyof",
     "indexed_access": "access",
     "intersection": "intersection",
     "union": "union",

packages/typescript-explorer/src/view/typeTreeView.ts

@@ -1,4 +1,4 @@
-import { TypeInfo, TypeId, getTypeInfoChildren, SymbolInfo, SignatureInfo } from '@ts-expand-type/api'
+import { TypeInfo, TypeId, getTypeInfoChildren, SymbolInfo, SignatureInfo, IndexInfo } from '@ts-expand-type/api'
 import assert = require('assert');
 import * as vscode from 'vscode'
 import * as ts from 'typescript'
@@ -87,6 +87,10 @@ abstract class TypeTreeItem extends vscode.TreeItem {
         return new SignatureNode(signature, this.provider, this)
     }
 
+    createIndexNode(indexInfo: IndexInfo) {
+        return new IndexNode(indexInfo, this.provider, this)
+    }
+
     getSignatureChildren(signature: SignatureInfo): TypeNode[] {
         return [
             ...signature.parameters.map(param => this.createChildTypeNode(param)),
@@ -136,8 +140,11 @@ class TypeNode extends TypeTreeItem {
 
         switch(kind) {
             case "object": {
-                const { properties, indexInfos } = this.typeTree
-                return properties.map(toTreeNode)
+                const { properties, indexInfos = [] } = this.typeTree
+                return [
+                    ...indexInfos.map(info => this.createIndexNode(info)),
+                    ...properties.map(toTreeNode),
+                ]
             }
 
             case "function": {
@@ -194,9 +201,27 @@ class SignatureNode extends TypeTreeItem {
     }
 }
 
+class IndexNode extends TypeTreeItem {
+    constructor(
+        private indexInfo: IndexInfo,
+        provider: TypeTreeProvider,
+        parent: TypeTreeItem|undefined
+    ) {
+        super(indexInfo.parameterSymbol?.name ?? "", vscode.TreeItemCollapsibleState.Collapsed, provider, parent)
+        this.description = "index"
+    }
+
+    getChildren() {
+        return [
+            ...this.indexInfo.keyType ? [this.createChildTypeNode(this.indexInfo.keyType, { purpose: 'index_type'})] : [],
+            ...this.indexInfo.type ? [this.createChildTypeNode(this.indexInfo.type, { purpose: 'index_value_type'})] : [],
+        ]
+    }
+}
+
 type TypeNodeArgs = {
-    purpose?: 'return',
-    optional?: boolean
+    purpose?: 'return'|'index_type'|'index_value_type',
+    optional?: boolean,
 }
 
 class TypeNodeGroup extends TypeTreeItem {
@@ -214,8 +239,8 @@ class TypeNodeGroup extends TypeTreeItem {
     }
 }
 
-function generateTypeNodeMeta(info: ResolvedTypeInfo, dimension: number, args?: TypeNodeArgs) {
-    const isOptional = info.symbolMeta?.optional || args?.optional || ((info.symbolMeta?.flags ?? 0) & ts.SymbolFlags.Optional)
+function generateTypeNodeMeta(info: ResolvedTypeInfo, dimension: number, {purpose, optional}: TypeNodeArgs = {}) {
+    const isOptional = info.symbolMeta?.optional || optional || ((info.symbolMeta?.flags ?? 0) & ts.SymbolFlags.Optional)
 
     let description = getBaseDescription()
     description += "[]".repeat(dimension)
@@ -232,8 +257,14 @@ function generateTypeNodeMeta(info: ResolvedTypeInfo, dimension: number, args?:
     }
 
     function getLabel() {
-        if(args?.purpose === 'return') {
-            return "<return>"
+        const nameByPurpose: Partial<Record<NonNullable<TypeNodeArgs['purpose']>, string>> = {
+            return: "<return>",
+            index_type: "<index type>",
+            index_value_type: "<type>",
+        }
+
+        if(purpose && purpose in nameByPurpose) {
+            return nameByPurpose[purpose]!
         }
 
         return !info.symbolMeta?.anonymous ? (info.symbolMeta?.name ?? "") : ""

tests/baselines/reference/mapped.tree

@@ -1,7 +1,7 @@
 === mapped.ts ===
 
 type mapped = { [index: string]: number }
-> mapped --- {"kind":"object","properties":[],"indexInfos":[{"keyType":{"kind":"primitive","primitive":"string","id":15},"type":{"kind":"primitive","primitive":"number","id":16}}],"symbolMeta":{"name":"mapped","flags":524288},"id":86}
+> mapped --- {"kind":"object","properties":[],"indexInfos":[{"keyType":{"kind":"primitive","primitive":"string","id":15},"type":{"kind":"primitive","primitive":"number","id":16},"parameterSymbol":{"name":"index","flags":1}}],"symbolMeta":{"name":"mapped","flags":524288},"id":86}
 > { [index: string]: number }
 > [index: string]: number
 > [index: string]: number

tests/baselines/reference/mappedParam.merged.types

@@ -0,0 +1,9 @@
+=== mappedParam.ts ===
+
+type mappedType2 = { [P in 'a'|'b'|'c']: P}
+> mappedType2 --- { a: "a"; b: "b"; c: "c"; }
+> { [P in 'a'|'b'|'c']: P}
+> P in 'a'|'b'|'c'
+> P --- P
+> P
+> P --- P

tests/baselines/reference/mappedParam.tree

@@ -0,0 +1,9 @@
+=== mappedParam.ts ===
+
+type mappedType2 = { [P in 'a'|'b'|'c']: P}
+> mappedType2 --- {"kind":"object","properties":[{"kind":"string_literal","value":"a","symbolMeta":{"name":"a","flags":33554436},"id":88},{"kind":"string_literal","value":"b","symbolMeta":{"name":"b","flags":33554436},"id":90},{"kind":"string_literal","value":"c","symbolMeta":{"name":"c","flags":33554436},"id":92}],"indexInfos":[{"keyType":{"kind":"union","types":[{"kind":"reference","id":88},{"kind":"reference","id":90},{"kind":"reference","id":92}],"id":94},"type":{"kind":"type_parameter","symbolMeta":{"name":"P","flags":262144},"id":87},"parameterSymbol":{"name":"P","flags":262144}}],"symbolMeta":{"name":"mappedType2","flags":524288},"id":86}
+> { [P in 'a'|'b'|'c']: P}
+> P in 'a'|'b'|'c'
+> P --- {"kind":"type_parameter","symbolMeta":{"name":"P","flags":262144},"id":87}
+> P
+> P --- {"kind":"type_parameter","symbolMeta":{"name":"P","flags":262144},"id":87}

tests/baselines/reference/partial.tree

@@ -3,7 +3,7 @@
 type partialUnion = Partial<{a: string}|{b: string}>
 > partialUnion --- {"kind":"union","types":[{"kind":"object","properties":[{"kind":"primitive","primitive":"string","symbolMeta":{"name":"a","flags":50331652},"id":15}],"indexInfos":[],"symbolMeta":{"name":"__type","flags":2048,"anonymous":true},"id":93},{"kind":"object","properties":[{"kind":"reference","symbolMeta":{"name":"b","flags":50331652},"id":15}],"indexInfos":[],"symbolMeta":{"name":"__type","flags":2048,"anonymous":true},"id":95}],"symbolMeta":{"name":"partialUnion","flags":524288},"id":97}
 > Partial<{a: string}|{b: string}>
-> Partial --- {"kind":"object","properties":[],"indexInfos":[{"keyType":{"kind":"index","indexOf":{"kind":"type_parameter","symbolMeta":{"name":"T","flags":262144},"id":87},"id":89},"type":{"kind":"indexed_access","indexType":{"kind":"type_parameter","symbolMeta":{"name":"P","flags":262144},"id":88},"objectType":{"kind":"reference","symbolMeta":{"name":"T","flags":262144},"id":87},"id":99}}],"symbolMeta":{"name":"Partial","flags":524288},"id":86}
+> Partial --- {"kind":"object","properties":[],"indexInfos":[{"keyType":{"kind":"index","indexOf":{"kind":"type_parameter","symbolMeta":{"name":"T","flags":262144},"id":87},"id":89},"type":{"kind":"indexed_access","indexType":{"kind":"type_parameter","symbolMeta":{"name":"P","flags":262144},"id":88},"objectType":{"kind":"reference","symbolMeta":{"name":"T","flags":262144},"id":87},"id":99},"parameterSymbol":{"name":"P","flags":262144}}],"symbolMeta":{"name":"Partial","flags":524288},"id":86}
 > {a: string}|{b: string}
 > {a: string}|{b: string}
 > {a: string}|{b: string}

tests/baselines/reference/pick.tree

@@ -20,7 +20,7 @@ type p = Pick<t, "a"|"d"> & {b: "asd", d: { b: "c" }}
 > Pick<t, "a"|"d"> & {b: "asd", d: { b: "c" }}
 > Pick<t, "a"|"d"> & {b: "asd", d: { b: "c" }}
 > Pick<t, "a"|"d">
-> Pick --- {"kind":"object","properties":[],"indexInfos":[{"keyType":{"kind":"type_parameter","symbolMeta":{"name":"K","flags":262144},"id":94},"type":{"kind":"indexed_access","indexType":{"kind":"type_parameter","symbolMeta":{"name":"P","flags":262144},"id":95},"objectType":{"kind":"type_parameter","symbolMeta":{"name":"T","flags":262144},"id":93},"id":104}}],"symbolMeta":{"name":"Pick","flags":524288},"id":92}
+> Pick --- {"kind":"object","properties":[],"indexInfos":[{"keyType":{"kind":"type_parameter","symbolMeta":{"name":"K","flags":262144},"id":94},"type":{"kind":"indexed_access","indexType":{"kind":"type_parameter","symbolMeta":{"name":"P","flags":262144},"id":95},"objectType":{"kind":"type_parameter","symbolMeta":{"name":"T","flags":262144},"id":93},"id":104},"parameterSymbol":{"name":"P","flags":262144}}],"symbolMeta":{"name":"Pick","flags":524288},"id":92}
 > t, "a"|"d"
 > t
 > t --- {"kind":"object","properties":[{"kind":"string_literal","value":"b","symbolMeta":{"name":"a","flags":4},"id":87},{"kind":"string_literal","value":"d","symbolMeta":{"name":"c","flags":4},"id":89},{"kind":"object","properties":[{"kind":"reference","symbolMeta":{"name":"a","flags":4},"id":87}],"indexInfos":[],"symbolMeta":{"name":"d","flags":4},"id":91}],"indexInfos":[],"symbolMeta":{"name":"t","flags":524288},"id":86}

tests/cases/mappedParam.ts

@@ -0,0 +1 @@
+type mappedType2 = { [P in 'a'|'b'|'c']: P}