lodash/test/sortedIndexBy-methods.spec.js

import lodashStable from 'lodash';
import { _, slice, MAX_ARRAY_LENGTH, MAX_ARRAY_INDEX } from './utils';

describe('sortedIndexBy methods', () => {
    lodashStable.each(['sortedIndexBy', 'sortedLastIndexBy'], (methodName) => {
        const func = _[methodName];
        const isSortedIndexBy = methodName === 'sortedIndexBy';

        it(`\`_.${methodName}\` should provide correct \`iteratee\` arguments`, () => {
            let args;

            func([30, 50], 40, function () {
                args || (args = slice.call(arguments));
            });

            expect(args).toEqual([40]);
        });

        it(`\`_.${methodName}\` should work with \`_.property\` shorthands`, () => {
            const objects = [{ x: 30 }, { x: 50 }];
            const actual = func(objects, { x: 40 }, 'x');

            expect(actual).toBe(1);
        });

        it(`\`_.${methodName}\` should avoid calling iteratee when length is 0`, () => {
            const objects = [];
            const actual = func(objects, { x: 50 }, assert.fail);

            expect(actual).toBe(0);
        });

        it(`\`_.${methodName}\` should support arrays larger than \`MAX_ARRAY_LENGTH / 2\``, () => {
            lodashStable.each([Math.ceil(MAX_ARRAY_LENGTH / 2), MAX_ARRAY_LENGTH], (length) => {
                const array = [];
                const values = [MAX_ARRAY_LENGTH, NaN, undefined];

                array.length = length;

                lodashStable.each(values, (value) => {
                    let steps = 0;

                    const actual = func(array, value, (value) => {
                        steps++;
                        return value;
                    });

                    const expected = (
                        isSortedIndexBy ? !lodashStable.isNaN(value) : lodashStable.isFinite(value)
                    )
                        ? 0
                        : Math.min(length, MAX_ARRAY_INDEX);

                    expect(steps === 32 || steps === 33);
                    expect(actual).toBe(expected);
                });
            });
        });
    });
});