error-stack-accessors.js

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// Test the Error.prototype.stack getter/setter with various "fun" edge cases.

load(libdir + "asserts.js");

// Stack should be accessible in subclasses. The accessor should walk up the

// prototype chain.

assertEq(typeof Object.create(Error()).stack, "string");

assertEq(Object.create(Error.prototype).stack, "");

// Stack should be overridable in subclasses.

  let myError = Object.create(Error());

  myError.stack = 5;

  assertEq(myError.stack, 5);

  let myOtherError = Object.create(Error.prototype);

  myOtherError.stack = 2;

  assertEq(myOtherError.stack, 2);

// Should throw when there is no Error in the `this` object's prototype chain.

var obj = Object.create(null);

var desc = Object.getOwnPropertyDescriptor(Error.prototype, "stack");

Object.defineProperty(obj, "stack", desc);

assertThrowsInstanceOf(() => obj.stack, TypeError);

// Should throw with non-object `this` values.

assertThrowsInstanceOf(desc.set,                TypeError);

assertThrowsInstanceOf(desc.set.bind("string"), TypeError);

assertThrowsInstanceOf(desc.get,                TypeError);

assertThrowsInstanceOf(desc.get.bind("string"), TypeError);