short-circuit-number-0.js

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// Copyright (C) 2019 Leo Balter. All rights reserved.

// This code is governed by the BSD license found in the LICENSE file.

/*---

description: >

    Short circuit if the CoalesceExpressionHead is not undefined or null (0)

esid: sec-conditional-operator

info: |

    ConditionalExpression :

        ShortCircuitExpression

        ShortCircuitExpression ? AssignmentExpression : AssignmentExpression

    ShortCircuitExpression :

        LogicalORExpression

        CoalesceExpression

    CoalesceExpression :

        CoalesceExpressionHead ?? BitwiseORExpression

    CoalesceExpressionHead :

        CoalesceExpression

        BitwiseORExpression

    Runtime Semantics: Evaluation

    CoalesceExpression:CoalesceExpressionHead??BitwiseORExpression

    1. Let lref be the result of evaluating CoalesceExpressionHead.

    2. Let lval be ? GetValue(lref).

    3. If lval is undefined or null,

        a. Let rref be the result of evaluating BitwiseORExpression.

        b. Return ? GetValue(rref).

    4. Otherwise, return lval.

features: [coalesce-expression]

---*/

var x;

x = undefined;

x = 0 ?? 1;

assert.sameValue(x, 0, '0 ?? 1');

x = undefined;

x = 0 ?? null;

assert.sameValue(x, 0, '0 ?? null');

x = undefined;

x = 0 ?? undefined;

assert.sameValue(x, 0, '0 ?? undefined');

x = undefined;

x = 0 ?? null ?? undefined;

assert.sameValue(x, 0, '0 ?? null ?? undefined');

x = undefined;

x = 0 ?? undefined ?? null;

assert.sameValue(x, 0, '0 ?? undefined ?? null');

x = undefined;

x = 0 ?? null ?? null;

assert.sameValue(x, 0, '0 ?? null ?? null');

x = undefined;

x = 0 ?? undefined ?? undefined;

assert.sameValue(x, 0, '0 ?? null ?? null');

x = undefined;

x = null ?? 0 ?? null;

assert.sameValue(x, 0, 'null ?? 0 ?? null');

x = undefined;

x = null ?? 0 ?? undefined;

assert.sameValue(x, 0, 'null ?? 0 ?? undefined');

x = undefined;

x = undefined ?? 0 ?? null;

assert.sameValue(x, 0, 'undefined ?? 0 ?? null');

x = undefined;

x = undefined ?? 0 ?? undefined;

assert.sameValue(x, 0, 'undefined ?? 0 ?? undefined');

reportCompare(0, 0);