list-slice

inspired by Python list method : list.__getitem__ and list.__setitem__

Install

$ pnpm install list-slice

Usage

import { getitem, setitem, pop } from "list-slice"

getitem

• getitem(arr, index)
• getitem(arr, [stop])
• getitem(arr, [start, stop])
• getitem(arr, [start, stop, step])
• getitem(arr, { start, stop, step })

const arr = [1, 2, 3, 4, 5]
// python arr[2:]
getitem(arr, [2,,]) // [3, 4, 5]
// python arr[3::-1]
getitem(arr, [3,,-1]) // [4, 3, 2, 1]

[2,,] is different than [2,] or you can just use [2, null].

setitem

• setitem(arr, index, newItem)
• setitem(arr, [stop], newArr)
• setitem(arr, [start, stop], newArr)
• setitem(arr, [start, stop, step], newArr)
• setitem(arr, { start, stop, step }, newArr)

const arr = [1, 3, 4, 5]

// python arr[:] = [7, 8, 9]
setitem(arr, [], [7, 8, 9])
console.log(arr) // [7, 8, 9]

// python arr[2:] = [7, 8, 9]
setitem(arr, [2,,], [7, 8, 9])
console.log(arr) // [7, 8, 7, 8, 9]

pop

• pop(arr)
• pop(arr, index)

const arr = [1, 3, 4, 5]

// python arr.pop(0)
const first = pop(arr, 0)
console.log(first, arr) // 1 [3, 4, 5]

Handling Errors

python-like error name:

const a = getitem([1,2,3], 3)
          ^

SliceIndexError [RangeError]: array index out of range
    at file:///c:/Users/Administrator/Desktop/test.mjs:3:11
    at ModuleJob.run (internal/modules/esm/module_job.js:183:25)
    at async Loader.import (internal/modules/esm/loader.js:178:24)
    at async Object.loadESM (internal/process/esm_loader.js:68:5)
    at async handleMainPromise (internal/modules/run_main.js:59:12)

Bundler notes

It was exported with cjs,esm,iife format and named exports.

No export is transpiled for sake of modern syntax.

It can only run on node14+ and modern browsers.

Test

Coverage 100%

------------|---------|----------|---------|---------|-------------------
File        | % Stmts | % Branch | % Funcs | % Lines | Uncovered Line #s
------------|---------|----------|---------|---------|-------------------
All files   |     100 |      100 |     100 |     100 | 
 error.ts   |     100 |      100 |     100 |     100 | 
 getitem.ts |     100 |      100 |     100 |     100 | 
 index.ts   |     100 |      100 |     100 |     100 | 
 pop.ts     |     100 |      100 |     100 |     100 | 
 setitem.ts |     100 |      100 |     100 |     100 | 
 slice.ts   |     100 |      100 |     100 |     100 | 
------------|---------|----------|---------|---------|-------------------
Test Suites: 1 passed, 1 total
Tests:       47 passed, 47 total