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LibJS: Support mapFn argument of Array.from

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This commit is contained in:
tuqqu 2021-04-06 23:12:38 +03:00 • committed by Andreas Kling
parent bb9cd13a56
commit 7bd0384fa6
2 changed files with 115 additions and 33 deletions
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107
Userland/Libraries/LibJS/Tests/builtins/Array/Array.from.js
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@ -3,20 +3,32 @@ test("length is 1", () => {
});
describe("normal behavior", () => {
test("empty array", () => {
var a = Array.from([]);
test("empty array, no mapFn", () => {
const a = Array.from([]);
expect(a instanceof Array).toBeTrue();
expect(a).toHaveLength(0);
});
test("empty string", () => {
var a = Array.from("");
test("empty array, with mapFn", () => {
const a = Array.from([], n => n);
expect(a instanceof Array).toBeTrue();
expect(a).toHaveLength(0);
});
test("non-empty array", () => {
var a = Array.from([5, 8, 1]);
test("empty string, no mapFn", () => {
const a = Array.from("");
expect(a instanceof Array).toBeTrue();
expect(a).toHaveLength(0);
});
test("empty string, with mapFn", () => {
const a = Array.from("", n => n);
expect(a instanceof Array).toBeTrue();
expect(a).toHaveLength(0);
});
test("non-empty array, no mapFn", () => {
const a = Array.from([5, 8, 1]);
expect(a instanceof Array).toBeTrue();
expect(a).toHaveLength(3);
expect(a[0]).toBe(5);
@ -24,8 +36,17 @@ describe("normal behavior", () => {
expect(a[2]).toBe(1);
});
test("non-empty string", () => {
var a = Array.from("what");
test("non-empty array, with mapFn", () => {
const a = Array.from([5, 8, 1], n => ++n);
expect(a instanceof Array).toBeTrue();
expect(a).toHaveLength(3);
expect(a[0]).toBe(6);
expect(a[1]).toBe(9);
expect(a[2]).toBe(2);
});
test("non-empty string, no mapFn", () => {
const a = Array.from("what");
expect(a instanceof Array).toBeTrue();
expect(a).toHaveLength(4);
expect(a[0]).toBe("w");
@ -34,36 +55,66 @@ describe("normal behavior", () => {
expect(a[3]).toBe("t");
});
test("shallow array copy", () => {
var a = [1, 2, 3];
var b = Array.from([a]);
test("non-empty string, with mapFn", () => {
const a = Array.from("what", n => n + n);
expect(a instanceof Array).toBeTrue();
expect(a).toHaveLength(4);
expect(a[0]).toBe("ww");
expect(a[1]).toBe("hh");
expect(a[2]).toBe("aa");
expect(a[3]).toBe("tt");
});
test("shallow array copy, no mapFn", () => {
const a = [1, 2, 3];
const b = Array.from([a]);
expect(b instanceof Array).toBeTrue();
expect(b).toHaveLength(1);
b[0][0] = 4;
expect(a[0]).toBe(4);
});
test("from iterator", () => {
function rangeIterator(begin, end) {
return {
[Symbol.iterator]() {
let value = begin - 1;
return {
next() {
if (value < end) {
value += 1;
}
return { value: value, done: value >= end };
},
};
},
};
}
test("shallow array copy, with mapFn", () => {
const a = [1, 2, 3];
const b = Array.from([a], n => n.map(n => n + 2));
expect(b instanceof Array).toBeTrue();
expect(b).toHaveLength(1);
b[0][0] = 10;
expect(a[0]).toBe(1);
expect(b[0][0]).toBe(10);
expect(b[0][1]).toBe(4);
expect(b[0][2]).toBe(5);
});
var a = Array.from(rangeIterator(8, 10));
const rangeIterator = function (begin, end) {
return {
[Symbol.iterator]() {
let value = begin - 1;
return {
next() {
if (value < end) {
value += 1;
}
return { value: value, done: value >= end };
},
};
},
};
};
test("from iterator, no mapFn", () => {
const a = Array.from(rangeIterator(8, 10));
expect(a instanceof Array).toBeTrue();
expect(a).toHaveLength(2);
expect(a[0]).toBe(8);
expect(a[1]).toBe(9);
});
test("from iterator, with mapFn", () => {
const a = Array.from(rangeIterator(8, 10), n => --n);
expect(a instanceof Array).toBeTrue();
expect(a).toHaveLength(2);
expect(a[0]).toBe(7);
expect(a[1]).toBe(8);
});
});