balazsbotond/eslinq

"use strict";

import from from "../src/eslinq";
import { identity, constantFalse, constantTrue } from "./helpers";

describe(".all", () => {

    it("throws if it is called with a non-function argument", () => {
        expect(() => from([1]).all(0)).toThrowError("`matches` should be a function");
    });

    it("returns true when given an empty iterable and a constant true condition", () => {
        const original = [],
            expected = true,
            actual = from(original).all(constantTrue);
        expect(actual).toEqual(expected);
    });

    it("returns true when given an empty iterable and a constant false condition", () => {
        const original = [],
            expected = true,
            actual = from(original).all(constantFalse);
        expect(actual).toEqual(expected);
    });

    it("returns true when given a one-element iterable and a constant true condition", () => {
        const original = [1],
            expected = true,
            actual = from(original).all(constantTrue);
        expect(actual).toEqual(expected);
    });

    it("returns false when given a one-element iterable and a constant false condition", () => {
        const original = [1],
            expected = false,
            actual = from(original).all(constantFalse);
        expect(actual).toEqual(expected);
    });

    it("returns true if all elements match", () => {
        const original = [1, 2, 3],
            expected = true,
            matches = n => n < 4,
            actual = from(original).all(matches);
        expect(actual).toEqual(expected);
    });

    it("returns false if no elements match", () => {
        const original = [1, 2, 3],
            expected = false,
            matches = n => n >= 4,
            actual = from(original).all(matches);
        expect(actual).toEqual(expected);
    });

    it("returns false if one element doesn't match", () => {
        const original = [1, 2, 3],
            expected = false,
            matches = n => n < 3,
            actual = from(original).all(matches);
        expect(actual).toEqual(expected);
    });

    it("works if the condition returns non-boolean truthy values", () => {
        const original = [1, "1"];
        expect(from(original).all(identity)).toBe(true);
    });

    it("works if the condition returns non-boolean falsy values", () => {
        const cases = [0, undefined, NaN, ""];
        for (let c of cases)
            expect(from([c]).all(identity)).toBe(false);
    });

});