RGBCube/serenity
1
Fork 0
mirror of https://github.com/RGBCube/serenity synced 2025-06-01 09:58:14 +00:00
Code Issues Activity Actions

LibJS: Implement proposed Array.prototype.findLast{,Index}

Browse source 
Proposal: https://tc39.es/proposal-array-find-from-last/
This commit is contained in:
davidot 2021-08-03 14:12:47 +02:00 • committed by Linus Groh
parent 44da58c0b2
commit b6523906b3
5 changed files with 229 additions and 0 deletions
Download patch file Download diff file Expand all files Collapse all files

61
Userland/Libraries/LibJS/Tests/builtins/Array/Array.prototype.findLast.js Normal file
View file

@ -0,0 +1,61 @@
test("length is 1", () => {
expect(Array.prototype.findLast).toHaveLength(1);
});
describe("errors", () => {
test("callback must be a function", () => {
expect(() => {
[].findLast(undefined);
}).toThrowWithMessage(TypeError, "undefined is not a function");
});
});
describe("normal behavior", () => {
test("basic functionality", () => {
var array = ["hello", "friends", 1, 2, false];
expect(array.findLast(value => value === "hello")).toBe("hello");
expect(array.findLast((value, index, arr) => index === 1)).toBe("friends");
expect(array.findLast(value => value == "1")).toBe(1);
expect(array.findLast(value => value === 1)).toBe(1);
expect(array.findLast(value => typeof value !== "string")).toBeFalse();
expect(array.findLast(value => typeof value === "boolean")).toBeFalse();
expect(array.findLast(value => typeof value === "string")).toBe("friends");
expect(array.findLast(value => value > 1)).toBe(2);
expect(array.findLast(value => value >= 1)).toBe(2);
expect(array.findLast(value => value > 1 && value < 3)).toBe(2);
expect(array.findLast(value => value > 100)).toBeUndefined();
expect([].findLast(value => value === 1)).toBeUndefined();
});
test("never calls callback with empty array", () => {
var callbackCalled = 0;
expect(
[].findLast(() => {
callbackCalled++;
})
).toBeUndefined();
expect(callbackCalled).toBe(0);
});
test("calls callback once for every item", () => {
var callbackCalled = 0;
expect(
[1, 2, 3].findLast(() => {
callbackCalled++;
})
).toBeUndefined();
expect(callbackCalled).toBe(3);
});
test("empty slots are treated as undefined", () => {
var callbackCalled = 0;
expect(
[1, , , "foo", , undefined, , , 6].findLast(value => {
callbackCalled++;
return value === undefined;
})
).toBeUndefined();
expect(callbackCalled).toBe(2);
});
});

61
Userland/Libraries/LibJS/Tests/builtins/Array/Array.prototype.findLastIndex.js Normal file
View file

@ -0,0 +1,61 @@
test("length is 1", () => {
expect(Array.prototype.findLastIndex).toHaveLength(1);
});
describe("errors", () => {
test("callback must be a function", () => {
expect(() => {
[].findLastIndex(undefined);
}).toThrowWithMessage(TypeError, "undefined is not a function");
});
});
describe("normal behavior", () => {
test("basic functionality", () => {
var array = ["hello", "friends", 1, 2, false];
expect(array.findLastIndex(value => value === "hello")).toBe(0);
expect(array.findLastIndex((value, index, arr) => index === 1)).toBe(1);
expect(array.findLastIndex(value => value == "1")).toBe(2);
expect(array.findLastIndex(value => value === 1)).toBe(2);
expect(array.findLastIndex(value => typeof value !== "string")).toBe(4);
expect(array.findLastIndex(value => typeof value === "boolean")).toBe(4);
expect(array.findLastIndex(value => typeof value === "string")).toBe(1);
expect(array.findLastIndex(value => value > 1)).toBe(3);
expect(array.findLastIndex(value => value >= 1)).toBe(3);
expect(array.findLastIndex(value => value > 1 && value < 3)).toBe(3);
expect(array.findLastIndex(value => value > 100)).toBe(-1);
expect([].findLastIndex(value => value === 1)).toBe(-1);
});
test("never calls callback with empty array", () => {
var callbackCalled = 0;
expect(
[].findLastIndex(() => {
callbackCalled++;
})
).toBe(-1);
expect(callbackCalled).toBe(0);
});
test("calls callback once for every item", () => {
var callbackCalled = 0;
expect(
[1, 2, 3].findLastIndex(() => {
callbackCalled++;
})
).toBe(-1);
expect(callbackCalled).toBe(3);
});
test("empty slots are treated as undefined", () => {
var callbackCalled = 0;
expect(
[1, , , "foo", , undefined, , , 6].findLastIndex(value => {
callbackCalled++;
return value === undefined;
})
).toBe(7);
expect(callbackCalled).toBe(2);
});
});