unscopables-proto.js

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// @@unscopables treats properties found on prototype chains the same as other

// properties.

const x = "global x";

const y = "global y";

// obj[@@unscopables].x works when obj.x is inherited via the prototype chain.

let proto = {x: "object x", y: "object y"};

let env = Object.create(proto);

env[Symbol.unscopables] = {x: true, y: false};

with (env) {

    assertEq(x, "global x");

    assertEq(delete x, false);

    assertEq(y, "object y");

assertEq(env.x, "object x");

// @@unscopables works if is inherited via the prototype chain.

env = {

    x: "object",

    [Symbol.unscopables]: {x: true, y: true}

};

for (let i = 0; i < 50; i++)

    env = Object.create(env);

env.y = 1;

with (env) {

    assertEq(x, "global x");

    assertEq(y, "global y");

// @@unscopables works if the obj[@@unscopables][id] property is inherited.

env = {

    x: "object",

    [Symbol.unscopables]: Object.create({x: true})

};

with (env)

    assertEq(x, "global x");

reportCompare(0, 0);