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| 1 | +import addedDiff from "../src/added"; |
| 2 | + |
| 3 | +describe("Prototype pollution", () => { |
| 4 | + test("Demonstrate prototype pollution globally across all objects", () => { |
| 5 | + const a = {}; |
| 6 | + const b = new Object(); |
| 7 | + |
| 8 | + expect(a.hello).toBeUndefined(); |
| 9 | + expect(b.hello).toBeUndefined(); |
| 10 | + expect({}.hello).toBeUndefined(); |
| 11 | + |
| 12 | + b.__proto__.hello = "world"; |
| 13 | + |
| 14 | + expect(a.hello).toBe("world"); |
| 15 | + expect(b.hello).toBe("world"); |
| 16 | + expect({}.hello).toBe("world"); |
| 17 | + }); |
| 18 | + |
| 19 | + test("addedDiff does not pollute global prototype when running diff with added `__proto__` key", () => { |
| 20 | + const a = { role: "user" }; |
| 21 | + const b = JSON.parse('{ "__proto__": { "role": "admin" } }'); |
| 22 | + |
| 23 | + expect(a.role).toBe("user"); |
| 24 | + expect(a.__proto__.role).toBeUndefined(); |
| 25 | + expect(b.role).toBeUndefined(); |
| 26 | + expect(b.__proto__.role).toBe("admin"); |
| 27 | + expect({}.role).toBeUndefined(); |
| 28 | + expect({}.__proto__role).toBeUndefined(); |
| 29 | + |
| 30 | + const difference = addedDiff(a, b); |
| 31 | + |
| 32 | + expect(a.role).toBe("user"); |
| 33 | + expect(a.__proto__.role).toBeUndefined(); |
| 34 | + expect(b.__proto__.role).toBe("admin"); |
| 35 | + expect(b.role).toBeUndefined(); |
| 36 | + expect({}.role).toBeUndefined(); |
| 37 | + expect({}.__proto__role).toBeUndefined(); |
| 38 | + |
| 39 | + expect(difference).toEqual({ __proto__: { role: "admin" } }); |
| 40 | + }); |
| 41 | + |
| 42 | + test("addedDiff does not pollute global prototype when running diff with added `__proto__` key generated from JSON.parse and mutating original left hand object", () => { |
| 43 | + let a = { role: "user" }; |
| 44 | + // Note: Don't trust `JSON.parse`!!! |
| 45 | + const b = JSON.parse('{ "__proto__": { "role": "admin" } }'); |
| 46 | + |
| 47 | + expect(a.role).toBe("user"); |
| 48 | + expect(a.__proto__.role).toBeUndefined(); |
| 49 | + expect(b.role).toBeUndefined(); |
| 50 | + expect(b.__proto__.role).toBe("admin"); |
| 51 | + expect({}.role).toBeUndefined(); |
| 52 | + expect({}.__proto__role).toBeUndefined(); |
| 53 | + |
| 54 | + // Note: although this does not pollute the global proto, it does pollute the original object. (Don't mutate kids!) |
| 55 | + a = addedDiff(a, b); |
| 56 | + |
| 57 | + expect(a.role).toBe("admin"); |
| 58 | + expect(a.__proto__.role).toBe("admin"); |
| 59 | + expect(b.__proto__.role).toBe("admin"); |
| 60 | + expect(b.role).toBeUndefined(); |
| 61 | + expect({}.role).toBeUndefined(); |
| 62 | + expect({}.__proto__role).toBeUndefined(); |
| 63 | + }); |
| 64 | + |
| 65 | + test("addedDiff does not pollute global prototype or original object when running diff with added `__proto__` key", () => { |
| 66 | + let a = { role: "user" }; |
| 67 | + const b = { __proto__: { role: "admin" } }; |
| 68 | + |
| 69 | + expect(a.role).toBe("user"); |
| 70 | + expect(a.__proto__.role).toBeUndefined(); |
| 71 | + expect(b.role).toBe("admin"); |
| 72 | + expect(b.__proto__.role).toBe("admin"); |
| 73 | + expect({}.role).toBeUndefined(); |
| 74 | + expect({}.__proto__role).toBeUndefined(); |
| 75 | + |
| 76 | + a = addedDiff(a, b); |
| 77 | + |
| 78 | + expect(a.role).toBeUndefined(); |
| 79 | + expect(a.__proto__.role).toBeUndefined(); |
| 80 | + expect(b.role).toBe("admin"); |
| 81 | + expect(b.__proto__.role).toBe("admin"); |
| 82 | + expect({}.role).toBeUndefined(); |
| 83 | + expect({}.__proto__role).toBeUndefined(); |
| 84 | + }); |
| 85 | +}); |
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