OverlayScrollbars/tests/core/utils/extend.test.ts

import { extend } from 'core/utils/extend';
import { isPlainObject } from 'core/utils/types';

//type DeepPartial<T> = T extends object ? { [K in keyof T]?: DeepPartial<T[K]> } : T
type Deep = {
    foo?: {
        bar?: boolean,
        baz?: boolean
    },
    foo2?: Document
};
type Settings = {
    xnumber0?: null,
    xnumber1?: number | null,
    xnumber2?: number | null,
    xstring1?: string,
    xstring2?: string,
    xxx?: string
};
type NestedArray = {
    arr: Array<any> | object
};

//https://github.com/jquery/jquery/blob/master/test/unit/core.js#L965
describe('extend', () => {
    test('equals object assign', () => {
        let settings: Settings = { xnumber1: 5, xnumber2: 7, xstring1: "peter", xstring2: "pan" };
        const options: Settings = { xnumber2: 1, xstring2: "x", xxx: "newstring" };
        const optionsCopy: Settings = { xnumber2: 1, xstring2: "x", xxx: "newstring" };
        const merged: Settings = { xnumber1: 5, xnumber2: 1, xstring1: "peter", xstring2: "x", xxx: "newstring" };

        extend(settings, options);
        expect(settings).toEqual(merged);
        expect(options).toEqual(optionsCopy);

        extend(settings, null, options);
        expect(settings).toEqual(merged);
        expect(options).toEqual(optionsCopy);


        const deep1: Deep = { foo: { bar: true } };
        const deep2: Deep = { foo: { baz: true }, foo2: document };
        const deep2copy: Deep = { foo: { baz: true }, foo2: document };
        const deepmerged: Deep = { foo: { bar: true, baz: true }, foo2: document };

        extend(deep1, deep2);
        expect(deep1.foo).toEqual(deepmerged.foo);
        expect(deep2.foo).toEqual(deep2copy.foo);
        expect(deep1.foo2).toBe(document);


        const arr = [1, 2, 3];
        const nestedArray: NestedArray = { arr: arr };

        expect(extend({}, nestedArray).arr).not.toBe(arr);
        expect(Array.isArray(extend({ arr: {} }, nestedArray).arr)).toBeTruthy();
        expect(Array.isArray(extend({ arr: {} }, nestedArray).arr)).toBeTruthy();
        expect(isPlainObject(extend({ arr: arr }, { arr: {} }).arr)).toBeTruthy();

        let empty = {};
        const optionsWithLength = { "foo": { "length": -1 } };


        extend(empty, optionsWithLength);
        expect(empty["foo"]).toEqual(optionsWithLength["foo"]);

        empty = {};
        const optionsWithDate = { "foo": { "date": new Date() } };


        extend(empty, optionsWithDate);
        expect(empty["foo"]).toEqual(optionsWithDate["foo"]);

        /** @constructor */
        const myKlass = function () { };
        // @ts-ignore
        const customObject = new myKlass();
        const optionsWithCustomObject = { "foo": { "date": customObject } };
        empty = {};

        extend(empty, optionsWithCustomObject);
        expect(empty["foo"] && empty["foo"]["date"] === customObject).toBeTruthy();

        // Makes the class a little more realistic
        myKlass.prototype = { "someMethod": function () { } };
        empty = {};

        extend(empty, optionsWithCustomObject);
        expect(empty["foo"] && empty["foo"]["date"] === customObject).toBeTruthy();

        const MyNumber = Number;

        var ret: any = extend({ foo: 4 }, { foo: new MyNumber(5) });
        expect(parseInt(ret.foo?.toString() as string, 10) === 5).toBeTruthy();

        let nullUndef = extend({}, options, { xnumber2: null });
        expect(nullUndef.xnumber2).toBe(null);

        // @ts-ignore
        nullUndef = extend({}, options, { xnumber2: undefined });
        expect(nullUndef.xnumber2).toBe(options.xnumber2);

        // @ts-ignore
        nullUndef = extend({}, options, { xnumber0: null });
        expect(nullUndef.xnumber0).toBe(null);

        const target = {};
        const recursive = { foo: target, bar: 5 };

        extend(target, recursive);
        expect(target).toEqual({ bar: 5 });

        ret = extend({ foo: [] }, { foo: [0] });
        expect(ret.foo?.length).toBe(1);

        ret = extend({ foo: "1,2,3" }, { foo: [1, 2, 3] });
        expect(typeof ret.foo !== "string").toBeTruthy();

        ret = extend({ foo: "bar" }, { foo: null });
        expect(typeof ret.foo !== "undefined").toBeTruthy();

        const obj = { foo: null };
        extend(obj, { foo: "notnull" });
        expect(obj.foo).toBe("notnull");

        const func: { (): void, key?: string } = () => { };
        extend(func, { key: "value" });
        expect(func.key).toBe("value");

        const defaults = { xnumber1: 5, xnumber2: 7, xstring1: "peter", xstring2: "pan" };
        const defaultsCopy = { xnumber1: 5, xnumber2: 7, xstring1: "peter", xstring2: "pan" };
        const options1 = { xnumber2: 1, xstring2: "x" };
        const options1Copy = { xnumber2: 1, xstring2: "x" };
        const options2 = { xstring2: "xx", xxx: "newstringx" };
        const options2Copy = { xstring2: "xx", xxx: "newstringx" };
        const merged2 = { xnumber1: 5, xnumber2: 1, xstring1: "peter", xstring2: "xx", xxx: "newstringx" };

        settings = extend({}, defaults, options1, options2);
        expect(settings).toEqual(merged2);
        expect(defaults).toEqual(defaultsCopy);
        expect(options1).toEqual(options1Copy);
        expect(options2).toEqual(options2Copy);

        expect(extend('', { foo: 1 })).toEqual({ foo: 1 });
        expect(extend(null, { foo: null, deep: { foo: null } })).toEqual({ foo: null, deep: { foo: null } });
        expect(extend(12, { foo: 1, deep: { foo: null, text: '' } })).toEqual({ foo: 1, deep: { foo: null, text: '' } });
    });
});