harmony 鸿蒙ArkCompiler Subsystem Changelog

2025-06-12
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ArkCompiler Subsystem Changelog

cl.arkcompiler.1 TS Compiler Targets ECMAScript 2021, Upgrading from ECMAScript 2017

Access Level

Other

Reason for Change

In the OpenHarmony SDK, the target option of the TypeScript compiler is changed from ES2017 to ES2021.

Change Impact

In rare scenarios where the code uses ES2018-ES2021 syntax features with syntax errors, which are masked using the @ts-nocheck or @ts-ignore comment:

Before the change, these syntax errors are masked using comments, and the compilation is successful.

After the change, the check rules for these syntaxes are enhanced, and a compilation error may be reported.

Start API Level

Change Since

OpenHarmony SDK 5.0.0.19

Key API/Component Changes

N/A

Adaptation Guide

Delete the @ts-nocheck and @ts-ignore comments and perform adaptation based on the compilation error messages. Refer to the examples below.

ES2018 Feature: rest Property

// @ts-ignore
const {a, ...remaning, b} = {a: 1, b: 2, c: 3, d: 4};
//           ~~~~~~~~
// Masked error: A rest element must be last in a destructuring pattern.

Suggestion: Delete the @ts-ignore comment and place the rest property at the end.

const {a, b, ...remaning} = {a: 1, b: 2, c: 3, d: 4};

ES2020 Feature: Optional Chaining Operator

const object = { property: "hi" };
// @ts-ignore
object?.property = "hello";
// ~~~~~~~~~~~~~ 
// Masked error: The left-hand side of an assignment expression may not be an optional property access.

Suggestion: Delete the @ts-ignore comment, check whether the object is null, and then assign a value.

const object = { property: "hi" };
if (object !== undefined) {
    object.property = "hello";
}

ES2020 Feature: Nullish Coalescing Operator

// @ts-nocheck
let a = null||undefined ?? "foo";
//      ~~~~~~~~~~~~~~~~~
// Masked error: '||' and '??' operations cannot be mixed without parentheses.
let b = true && undefined ?? "foo";
//      ~~~~~~~~~~~~~~~~~
// Masked error: '&&' and '??' operations cannot be mixed without parentheses.

Suggestion: Delete the @ts-nocheck comment and add parentheses to ensure that the operation sequence meets the expectation.

let a = (null||undefined) ?? "foo";
let b = (true && undefined) ?? "foo";

For other scenarios with incompatible changes, delete the @ts-nocheck and @ts-ignore comments and rectify the fault based on the compilation error messages.

You can also set targetESVersion to ES2017 in the project-level build-profile.json5 file to continue using ECMAScript 2017.