Performant ArkTS Programming: Best Practices for High-Efficiency Code
Source: Dev.to
Introduction
ArkTS offers developers a powerful, TypeScript‑like syntax with optimizations designed for better runtime performance. Writing performant applications requires more than just using the right framework; it also demands awareness of low‑level optimizations. In this article we explore real‑world practices for ArkTS that help you write faster, leaner, and more efficient code, whether you’re building user interfaces, computing logic, or handling data structures.
Use const for Invariant Variables
If a variable’s value never changes, define it with const. This allows the engine to optimize memory and access paths more effectively.
const index = 10000;Avoid Mixing Integer and Floating‑Point Types
ArkTS distinguishes between integer and floating‑point types under the hood. Mixing them can degrade performance due to type re‑evaluation.
let num = 1;
num = 1.1; // ❌ Don't mix types after initializationAvoid Arithmetic Overflow
Operations that exceed INT32_MAX or fall below INT32_MIN push the engine into slower execution paths. Avoid overflows in performance‑sensitive logic for operators such as +, -, *, **, &, and >>>.
Extract Constants Outside Loops
Repeatedly accessing class properties or static values inside a loop increases attribute‑lookup costs. Cache them outside the loop.
const info = Time.info[num - Time.start];
for (let index = 0x8000; index > 0x8; index >>= 1) {
if ((info & index) !== 0) {
total++;
}
}Prefer Parameter Passing Over Closures
Closures introduce memory and performance overhead. For hot paths, pass variables directly via function parameters.
function foo(arr: number[]): number {
return arr[0] + arr[1];
}Avoid Optional Parameters in Hot Paths
Optional parameters add extra undefined checks, slowing down execution. Use default values instead.
// Instead of this:
function add(a?: number, b?: number): number | undefined { /* ... */ }
// Use this:
function add(a: number = 0, b: number = 0): number {
return a + b;
}Use TypedArray for Numeric Data
When performing arithmetic, TypedArray (e.g., Int8Array, Float32Array) provides better performance than a regular Array.
const arr1 = new Int8Array([1, 2, 3]);
const arr2 = new Int8Array([4, 5, 6]);
let result = new Int8Array(3);Avoid Sparse Arrays
Sparse arrays (e.g., arr[9999] = 0) are stored as hash tables internally and are much slower to access. Always initialize arrays with contiguous elements when performance matters.
Avoid Union Arrays and Mixed Types
Combining different types (number | string) in one array leads to deoptimization. Stick to a single consistent type per array.
let arrInt: number[] = [1, 2, 3];
let arrStr: string[] = ["a", "b"];Avoid Frequent Exceptions
Throwing exceptions often creates costly stack frames, negatively impacting performance. Replace frequent exception throwing with conditional checks, especially inside loops.
Before optimization
function div(a: number, b: number): number {
if (a <= 0 || b <= 0) {
throw new Error('Invalid numbers.');
}
return a / b;
}
function sum(num: number): number {
let sum = 0;
try {
for (let t = 1; t < 100; t++) {
sum += div(t, num);
}
} catch (e) {
console.log(e.message);
}
return sum;
}After optimization
function div(a: number, b: number): number {
if (a <= 0 || b <= 0) {
return NaN;
}
return a / b;
}
function sum(num: number): number {
let sum = 0;
for (let t = 1; t < 100; t++) {
if (t <= 0 || num <= 0) {
console.log('Invalid numbers.');
}
sum += div(t, num);
}
return sum;
}Conclusion
Writing performant ArkTS code means minimizing unnecessary type changes, reducing memory usage, avoiding heavy exceptions, and using data types that align with the system. By integrating these best practices into your development workflow, you’ll not only write faster applications but also improve code maintainability and reliability in performance‑sensitive environments. If you’re developing with ArkTS or exploring HarmonyOS, adopting these small, focused changes can yield massive performance improvements. Happy coding!