TypeScriptToLua · Perryvw · Dec 9, 2019 · Dec 9, 2019
diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
@@ -13,7 +13,6 @@ jobs:
     steps:
       - uses: actions/checkout@v1
       - uses: actions/setup-node@v1
-      - run: npm install --global npm@6
       - run: npm ci
       - run: npm run lint
         env:
@@ -28,11 +27,10 @@ jobs:
 
     steps:
       - uses: actions/checkout@v1
-      - name: Use Node.js 8.5.0
+      - name: Use Node.js 12.13.1
         uses: actions/setup-node@v1
         with:
-          node-version: 8.5.0
-      - run: npm install --global npm@6
+          node-version: 12.13.1
       - run: npm ci
       - run: npm run build
       - run: npx jest --maxWorkers 2 --coverage

diff --git a/.github/workflows/release.yml b/.github/workflows/release.yml
@@ -14,7 +14,6 @@ jobs:
       - uses: actions/setup-node@v1
         with:
           registry-url: "https://registry.npmjs.org"
-      - run: npm install --global npm@6
       - run: npm ci
       - run: npm run build
       - run: npm publish

diff --git a/package.json b/package.json
@@ -36,7 +36,7 @@
         "tstl": "./dist/tstl.js"
     },
     "engines": {
-        "node": ">=8.5.0"
+        "node": ">=12.13.0"
     },
     "dependencies": {
         "resolve": "^1.13.1",

diff --git a/src/transformation/context/context.ts b/src/transformation/context/context.ts
@@ -1,7 +1,6 @@
 import * as ts from "typescript";
 import { CompilerOptions, LuaTarget } from "../../CompilerOptions";
 import * as lua from "../../LuaAST";
-import { flatMap } from "../../utils";
 import { unwrapVisitorResult } from "../utils/lua-ast";
 import { isFileModule } from "../utils/typescript";
 import { ExpressionLikeNode, ObjectVisitor, StatementLikeNode, VisitorMap } from "./visitors";
@@ -81,14 +80,14 @@ export class TransformationContext {
 
     public transformStatements(node: StatementLikeNode | readonly StatementLikeNode[]): lua.Statement[] {
         return Array.isArray(node)
-            ? flatMap(node, n => this.transformStatements(n))
+            ? node.flatMap(n => this.transformStatements(n))
             : // TODO: https://github.com/microsoft/TypeScript/pull/28916
               (this.transformNode(node as StatementLikeNode) as lua.Statement[]);
     }
 
     public superTransformStatements(node: StatementLikeNode | readonly StatementLikeNode[]): lua.Statement[] {
         return Array.isArray(node)
-            ? flatMap(node, n => this.superTransformStatements(n))
+            ? node.flatMap(n => this.superTransformStatements(n))
             : // TODO: https://github.com/microsoft/TypeScript/pull/28916
               (this.superTransformNode(node as StatementLikeNode) as lua.Statement[]);
     }

diff --git a/src/transformation/utils/annotations.ts b/src/transformation/utils/annotations.ts
@@ -1,5 +1,4 @@
 import * as ts from "typescript";
-import { flatMap } from "../../utils";
 import { TransformationContext } from "../context";
 import { findFirstNodeAbove, inferAssignedType } from "./typescript";
 
@@ -102,7 +101,7 @@ export function getFileAnnotations(sourceFile: ts.SourceFile): AnnotationsMap {
         // Manually collect jsDoc because `getJSDocTags` includes tags only from closest comment
         const jsDoc = sourceFile.statements[0].jsDoc;
         if (jsDoc) {
-            for (const tag of flatMap(jsDoc, x => x.tags ?? [])) {
+            for (const tag of jsDoc.flatMap(x => x.tags ?? [])) {
                 const tagName = tag.tagName.text;
                 const annotation = createAnnotation(tagName, tag.comment ? tag.comment.split(" ") : []);
                 if (annotation) {

diff --git a/src/transformation/utils/function-context.ts b/src/transformation/utils/function-context.ts
@@ -1,6 +1,5 @@
 import * as ts from "typescript";
 import { CompilerOptions } from "../../CompilerOptions";
-import { flatMap } from "../../utils";
 import { TransformationContext } from "../context";
 import { AnnotationKind, getFileAnnotations, getNodeAnnotations } from "./annotations";
 import { findFirstNodeAbove, getAllCallSignatures, inferAssignedType } from "./typescript";
@@ -107,7 +106,7 @@ function getSignatureDeclarations(
     context: TransformationContext,
     signatures: readonly ts.Signature[]
 ): ts.SignatureDeclaration[] {
-    return flatMap(signatures, signature => {
+    return signatures.flatMap(signature => {
         const signatureDeclaration = signature.getDeclaration();
         if (
             (ts.isFunctionExpression(signatureDeclaration) || ts.isArrowFunction(signatureDeclaration)) &&

diff --git a/src/transformation/utils/typescript/index.ts b/src/transformation/utils/typescript/index.ts
@@ -1,5 +1,4 @@
 import * as ts from "typescript";
-import { flatMap } from "../../../utils";
 import { TransformationContext } from "../../context";
 import { isDeclaration } from "./nodes";
 
@@ -90,7 +89,7 @@ export function inferAssignedType(context: TransformationContext, expression: ts
 }
 
 export function getAllCallSignatures(type: ts.Type): readonly ts.Signature[] {
-    return type.isUnion() ? flatMap(type.types, getAllCallSignatures) : type.getCallSignatures();
+    return type.isUnion() ? type.types.flatMap(getAllCallSignatures) : type.getCallSignatures();
 }
 
 // Returns true for expressions that may have effects when evaluated

diff --git a/src/transformation/visitors/binary-expression/destructuring-assignments.ts b/src/transformation/visitors/binary-expression/destructuring-assignments.ts
@@ -1,6 +1,5 @@
 import * as ts from "typescript";
 import * as lua from "../../../LuaAST";
-import { flatMap } from "../../../utils";
 import { TransformationContext } from "../../context";
 import { UnsupportedKind } from "../../utils/errors";
 import { LuaLibFeature, transformLuaLibFunction } from "../../utils/lualib";
@@ -57,7 +56,7 @@ function transformArrayLiteralAssignmentPattern(
     node: ts.ArrayLiteralExpression,
     root: lua.Expression
 ): lua.Statement[] {
-    return flatMap(node.elements, (element, index) => {
+    return node.elements.flatMap((element, index) => {
         const indexedRoot = lua.createTableIndexExpression(root, lua.createNumericLiteral(index + 1), element);
 
         switch (element.kind) {

diff --git a/src/transformation/visitors/loops/for.ts b/src/transformation/visitors/loops/for.ts
@@ -1,6 +1,5 @@
 import * as ts from "typescript";
 import * as lua from "../../../LuaAST";
-import { flatMap } from "../../../utils";
 import { FunctionVisitor } from "../../context";
 import { transformVariableDeclaration } from "../variable-declaration";
 import { transformLoopBody } from "./body";
@@ -11,7 +10,7 @@ export const transformForStatement: FunctionVisitor<ts.ForStatement> = (statemen
     if (statement.initializer) {
         if (ts.isVariableDeclarationList(statement.initializer)) {
             // local initializer = value
-            result.push(...flatMap(statement.initializer.declarations, d => transformVariableDeclaration(context, d)));
+            result.push(...statement.initializer.declarations.flatMap(d => transformVariableDeclaration(context, d)));
         } else {
             result.push(...context.transformStatements(ts.createExpressionStatement(statement.initializer)));
         }

diff --git a/src/transformation/visitors/variable-declaration.ts b/src/transformation/visitors/variable-declaration.ts
@@ -1,6 +1,6 @@
 import * as ts from "typescript";
 import * as lua from "../../LuaAST";
-import { assertNever, flatMap } from "../../utils";
+import { assertNever } from "../../utils";
 import { FunctionVisitor, TransformationContext } from "../context";
 import { isTupleReturnCall } from "../utils/annotations";
 import { validateAssignment } from "../utils/assignment-validation";
@@ -223,4 +223,4 @@ export function transformVariableDeclaration(
 }
 
 export const transformVariableStatement: FunctionVisitor<ts.VariableStatement> = (node, context) =>
-    flatMap(node.declarationList.declarations, declaration => transformVariableDeclaration(context, declaration));
+    node.declarationList.declarations.flatMap(declaration => transformVariableDeclaration(context, declaration));
diff --git a/src/utils.ts b/src/utils.ts
@@ -12,21 +12,6 @@ export function formatPathToLuaPath(filePath: string): string {
     return filePath.replace(/\.\//g, "").replace(/\//g, ".");
 }
 
-export function flatMap<T, U>(array: readonly T[], callback: (value: T, index: number) => U | readonly U[]): U[] {
-    const result: U[] = [];
-
-    for (const [index, value] of array.entries()) {
-        const mappedValue = callback(value, index);
-        if (Array.isArray(mappedValue)) {
-            result.push(...mappedValue);
-        } else {
-            result[result.length] = mappedValue as U;
-        }
-    }
-
-    return result;
-}
-
 type NoInfer<T> = [T][T extends any ? 0 : never];
 
 export function getOrUpdate<K, V>(

diff --git a/test/tsconfig.json b/test/tsconfig.json
@@ -5,8 +5,8 @@
         "strict": true,
         "noUnusedLocals": true,
         "noUnusedParameters": true,
-        "target": "es2017",
-        "lib": ["es2017"],
+        "target": "es2019",
+        "lib": ["es2019"],
         "types": ["node", "jest"],
         "experimentalDecorators": true,
 

diff --git a/test/unit/builtins/array.spec.ts b/test/unit/builtins/array.spec.ts
@@ -488,28 +488,26 @@ test.each([
 });
 
 test.each([
-    { array: [[]], expected: [] },
-    { array: [{ a: 1 }, { a: 2 }, { a: 3 }], expected: [{ a: 1 }, { a: 2 }, { a: 3 }] },
-    { array: [1, [2, 3], 4], expected: [1, 2, 3, 4] },
-    { array: [1, [2, 3], 4], depth: 0, expected: [1, [2, 3], 4] },
-    { array: [1, [[2], [3]], 4], expected: [1, [2], [3], 4] },
-    { array: [1, [[[2], [3]]], 4], depth: Infinity, expected: [1, 2, 3, 4] },
-])("array.flat (%p)", ({ array, depth, expected }) => {
-    // TODO: Node 12
-    util.testExpressionTemplate`${array}.flat(${depth})`.expectToEqual(expected);
+    { array: [[]] },
+    { array: [{ a: 1 }, { a: 2 }, { a: 3 }] },
+    { array: [1, [2, 3], 4] },
+    { array: [1, [2, 3], 4], depth: 0 },
+    { array: [1, [[2], [3]], 4] },
+    { array: [1, [[[2], [3]]], 4], depth: Infinity },
+])("array.flat (%p)", ({ array, depth }) => {
+    util.testExpressionTemplate`${array}.flat(${depth})`.expectToMatchJsResult();
 });
 
 test.each([
-    { array: [[]], map: <T>(v: T) => v, expected: [] },
-    { array: [1, 2, 3], map: (v: number) => ({ a: v * 2 }), expected: [{ a: 2 }, { a: 4 }, { a: 6 }] },
-    { array: [1, [2, 3], [4]], map: <T>(value: T) => value, expected: [1, 2, 3, 4] },
-    { array: [1, 2, 3], map: (v: number) => v * 2, expected: [2, 4, 6] },
-    { array: [1, 2, 3], map: (v: number) => [v, v * 2], expected: [1, 2, 2, 4, 3, 6] },
-    { array: [1, 2, 3], map: (v: number) => [v, [v]], expected: [1, [1], 2, [2], 3, [3]] },
-    { array: [1, 2, 3], map: (v: number, i: number) => [v * 2 * i], expected: [0, 4, 12] },
-])("array.flatMap (%p)", ({ array, map, expected }) => {
-    // TODO: Node 12
-    util.testExpressionTemplate`${array}.flatMap(${map})`.expectToEqual(expected);
+    { array: [[]], map: <T>(v: T) => v },
+    { array: [1, 2, 3], map: (v: number) => ({ a: v * 2 }) },
+    { array: [1, [2, 3], [4]], map: <T>(value: T) => value },
+    { array: [1, 2, 3], map: (v: number) => v * 2 },
+    { array: [1, 2, 3], map: (v: number) => [v, v * 2] },
+    { array: [1, 2, 3], map: (v: number) => [v, [v]] },
+    { array: [1, 2, 3], map: (v: number, i: number) => [v * 2 * i] },
+])("array.flatMap (%p)", ({ array, map }) => {
+    util.testExpressionTemplate`${array}.flatMap(${map})`.expectToMatchJsResult();
 });
 
 describe.each(["reduce", "reduceRight"])("array.%s", reduce => {

diff --git a/test/unit/builtins/numbers.spec.ts b/test/unit/builtins/numbers.spec.ts
@@ -1,4 +1,3 @@
-import { flatMap } from "../../../src/utils";
 import * as util from "../../util";
 
 test.each([
@@ -51,7 +50,7 @@ describe("Number", () => {
 
 const toStringRadixes = [undefined, 10, 2, 8, 9, 16, 17, 36, 36.9];
 const toStringValues = [-1, 0, 1, 1.5, 1024, 1.2];
-const toStringPairs = flatMap(toStringValues, value => toStringRadixes.map(radix => [value, radix] as const));
+const toStringPairs = toStringValues.flatMap(value => toStringRadixes.map(radix => [value, radix] as const));
 
 test.each(toStringPairs)("(%p).toString(%p)", (value, radix) => {
     util.testExpressionTemplate`(${value}).toString(${radix})`.expectToMatchJsResult();

diff --git a/test/unit/builtins/object.spec.ts b/test/unit/builtins/object.spec.ts
@@ -22,13 +22,9 @@ test.each([{}, { abc: "def" }, { abc: 3, def: "xyz" }])("Object.values (%p)", ob
     util.testExpressionTemplate`Object.values(${obj})`.expectToMatchJsResult();
 });
 
-// TODO: Jest 25: as const
-test.each<[string, object]>([
-    ["[]", []],
-    ['[["a", 1], ["b", 2]]', { a: 1, b: 2 }],
-    ['[["a", 1], ["a", 2]]', { a: 2 }],
-    ['new Map([["foo", "bar"]])', { foo: "bar" }],
-])("Object.fromEntries(%s)", (entries, expected) => {
-    // TODO: Node 12
-    util.testExpression`Object.fromEntries(${entries})`.expectToEqual(expected);
-});
+test.each(["[]", '[["a", 1], ["b", 2]]', '[["a", 1], ["a", 2]]', 'new Map([["foo", "bar"]])'])(
+    "Object.fromEntries(%s)",
+    entries => {
+        util.testExpression`Object.fromEntries(${entries})`.expectToMatchJsResult();
+    }
+);
diff --git a/tsconfig.json b/tsconfig.json
@@ -7,8 +7,8 @@
         "outDir": "./dist",
         "declaration": true,
         "sourceMap": true,
-        "target": "es2017",
-        "lib": ["es2017"],
+        "target": "es2019",
+        "lib": ["es2019"],
         "module": "commonjs",
         "stripInternal": true
     },