Fix destructuring evaluation order for initializers

src/testRunner/tsconfig.json

@@ -89,6 +89,7 @@
         "unittests/evaluation/asyncArrow.ts",
         "unittests/evaluation/asyncGenerator.ts",
         "unittests/evaluation/awaiter.ts",
+        "unittests/evaluation/destructuring.ts",
         "unittests/evaluation/forAwaitOf.ts",
         "unittests/evaluation/forOf.ts",
         "unittests/evaluation/optionalCall.ts",

src/testRunner/unittests/evaluation/destructuring.ts

@@ -0,0 +1,39 @@
+describe("unittests:: evaluation:: destructuring", () => {
+    // https://github.com/microsoft/TypeScript/issues/39205
+    describe("correct order for array destructuring evaluation and initializers", () => {
+        it("when element is undefined", () => {
+            const result = evaluator.evaluateTypeScript(`
+                export const output: any[] = [];
+                const order = (n: any): any => output.push(n);
+                let [{ [order(1)]: x } = order(0)] = [];
+            `, { target: ts.ScriptTarget.ES5 });
+            assert.deepEqual(result.output, [0, 1]);
+        });
+        it("when element is defined", async () => {
+            const result = evaluator.evaluateTypeScript(`
+                export const output: any[] = [];
+                const order = (n: any): any => output.push(n);
+                let [{ [order(1)]: x } = order(0)] = [{}];
+            `, { target: ts.ScriptTarget.ES5 });
+            assert.deepEqual(result.output, [1]);
+        });
+    });
+    describe("correct order for array destructuring evaluation and initializers with spread", () => {
+        it("ES5", () => {
+            const result = evaluator.evaluateTypeScript(`
+                export const output: any[] = [];
+                const order = (n: any): any => output.push(n);
+                let { [order(0)]: { [order(2)]: z } = order(1), ...w } = {} as any;
+                `, { target: ts.ScriptTarget.ES5 });
+            assert.deepEqual(result.output, [0, 1, 2]);
+        });
+        it("ES2015", () => {
+            const result = evaluator.evaluateTypeScript(`
+                export const output: any[] = [];
+                const order = (n: any): any => output.push(n);
+                let { [order(0)]: { [order(2)]: z } = order(1), ...w } = {} as any;
+                `, { target: ts.ScriptTarget.ES2015 });
+            assert.deepEqual(result.output, [0, 1, 2]);
+        });
+    });
+});