https://github.com/GoogleFeud/ts-zero-cost-iters

A typescript plugin which transpiles multiple array methods like map, filter, reduce, etc. into a single for loop.
https://github.com/GoogleFeud/ts-zero-cost-iters

optimization performance plugin typescript

Last synced: about 2 months ago
JSON representation

A typescript plugin which transpiles multiple array methods like map, filter, reduce, etc. into a single for loop.

• Host: GitHub
• URL: https://github.com/GoogleFeud/ts-zero-cost-iters
• Owner: GoogleFeud
• License: mit
• Created: 2021-07-22T06:06:48.000Z (about 3 years ago)
• Default Branch: main
• Last Pushed: 2021-07-23T07:13:48.000Z (about 3 years ago)
• Last Synced: 2024-07-01T00:21:44.467Z (3 months ago)
• Topics: optimization, performance, plugin, typescript
• Language: TypeScript
• Homepage:
• Size: 36.1 KB
• Stars: 6
• Watchers: 1
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

Awesome Lists containing this project

README

        
# ts-zero-cost-iters

`ts-zero-cost-iters` is a typescript plugin which combines array functions like `filter`, `map` and `reduce` into a single for loop. Example:

```ts

const array = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10];

const result = array.filter(num => num % 2 === 0).map(num => num * 2).join("+");

```

to:

```js

const array = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10];

var arrLen_1 = array.length, arrItem_1, i_1 = 0;

var result = "";

for (; i_1 < arrLen_1; i_1++) {

    arrItem_1 = array[i_1];

    if (!(arrItem_1 % 2 === 0))

        continue;

    result += arrItem_1 * 2 + (i_1 === arrLen_1 - 1 ? "" : "+");

}

```

## Install

You need the `ttypescript` package in order to use this:

```npm i ttypescript```

After that put this in your tsconfig.json:

```

"compilerOptions": {

//... other options

"plugins": [

        { "transform": "ts-macros" }

]

}

```

And run your code with `ttsc`

## ts-zero-cost-iters in-depth

### .length

If the chain ends with a `.length`, then the generated output will NEVER create a new array, it's just going to count the elements.

```ts

const result = array.filter(num => num % 2 === 0).length;

```

```js

var arrLen_1 = array.length, arrItem_1, i_1 = 0;

var result = 0;

for (; i_1 < arrLen_1; i_1++) {

    arrItem_1 = array[i_1];

    if (!(arrItem_1 % 2 === 0))

        continue;

    result++;

}

```