57 lines
1.6 KiB
JavaScript
57 lines
1.6 KiB
JavaScript
describe("errors", () => {
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test("invalid array length value", () => {
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var a = [1, 2, 3];
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[undefined, "foo", -1, Infinity, -Infinity, NaN].forEach(value => {
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expect(() => {
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a.length = value;
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}).toThrowWithMessage(RangeError, "Invalid array length");
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expect(a).toHaveLength(3);
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});
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});
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});
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describe("normal behavior", () => {
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test("extend array by setting length", () => {
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var a = [1, 2, 3];
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a.length = 5;
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expect(a).toEqual([1, 2, 3, undefined, undefined]);
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});
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test("truncate array by setting length", () => {
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var a = [1, 2, 3];
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a.length = 2;
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expect(a).toEqual([1, 2]);
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a.length = 0;
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expect(a).toEqual([]);
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});
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test("length value is coerced to number if possible", () => {
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var a = [1, 2, 3];
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a.length = "42";
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expect(a).toHaveLength(42);
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a.length = [];
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expect(a).toHaveLength(0);
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a.length = true;
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expect(a).toHaveLength(1);
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});
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test("setting a huge array length", () => {
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var a = [];
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a.length = 0x80000000;
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expect(a.length).toEqual(0x80000000);
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var b = [];
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b.length = 0x80000001;
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expect(b.length).toEqual(0x80000001);
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});
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test("should not remove non-configurable values", () => {
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var a = [1, undefined, 3];
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Object.defineProperty(a, 1, { configurable: false, value: 2 });
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expect(a.length).toEqual(3);
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expect((a.length = 1)).toEqual(1);
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expect(a.length).toEqual(2);
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expect(a[1]).toEqual(2);
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});
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});
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