__tests__/splice.ts - main - githubmirror/immutable-js

__tests__/splice.ts
68 строк2 KB
Julien Deniau
sort all imports via eslint
12 июн 2025, 01:23
12 июн 2025, 01:2367a4fa9
import { describe, expect, it } from '@jest/globals';
import fc from 'fast-check';
import { List, Range, Seq } from 'immutable';

describe('splice', () => {
  it('splices a sequence only removing elements', () => {
    expect(Seq([1, 2, 3]).splice(0, 1).toArray()).toEqual([2, 3]);
    expect(Seq([1, 2, 3]).splice(1, 1).toArray()).toEqual([1, 3]);
    expect(Seq([1, 2, 3]).splice(2, 1).toArray()).toEqual([1, 2]);
    expect(Seq([1, 2, 3]).splice(3, 1).toArray()).toEqual([1, 2, 3]);
  });

  it('splices a list only removing elements', () => {
    expect(List([1, 2, 3]).splice(0, 1).toArray()).toEqual([2, 3]);
    expect(List([1, 2, 3]).splice(1, 1).toArray()).toEqual([1, 3]);
    expect(List([1, 2, 3]).splice(2, 1).toArray()).toEqual([1, 2]);
    expect(List([1, 2, 3]).splice(3, 1).toArray()).toEqual([1, 2, 3]);
  });

  it('splicing by infinity', () => {
    const l = List(['a', 'b', 'c', 'd']);
    expect(l.splice(2, Infinity, 'x').toArray()).toEqual(['a', 'b', 'x']);
    expect(l.splice(Infinity, 2, 'x').toArray()).toEqual([
      'a',
      'b',
      'c',
      'd',
      'x',
    ]);

    const s = List(['a', 'b', 'c', 'd']);
    expect(s.splice(2, Infinity, 'x').toArray()).toEqual(['a', 'b', 'x']);
    expect(s.splice(Infinity, 2, 'x').toArray()).toEqual([
      'a',
      'b',
      'c',
      'd',
      'x',
    ]);
  });

  it('has the same behavior as array splice in known edge cases', () => {
    // arbitrary numbers that sum to 31
    const a = Range(0, 49).toArray();
    const v = List(a);
    a.splice(-18, 0, 0);
    expect(v.splice(-18, 0, 0).toList().toArray()).toEqual(a);
  });

  it('has the same behavior as array splice', () => {
    fc.assert(
      fc.property(
        fc.array(fc.integer()),
        fc.integer(),
        fc.integer(),
        fc.array(fc.integer()),
        (values, index, removeNum, insertValues) => {
          const v = List(values);
          const a = values.slice(); // clone

          const splicedV = v.splice(index, removeNum, ...insertValues); // persistent
          a.splice(index, removeNum, ...insertValues); // mutative
          expect(splicedV.toArray()).toEqual(a);
        }
      )
    );
  });
});