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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');
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