a7bddc02ba
`??=` is being merged into the Logical Assignment Operator proposal, and the overall proposal will wait until nullish coalescing is finalized.
50 lines
814 B
JavaScript
50 lines
814 B
JavaScript
var x = undefined;
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var sets = 0;
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var obj = {
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get x() {
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return x;
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},
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set x(value) {
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sets++;
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x = value;
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},
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};
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assert.equal(obj.x ??= 1, 1);
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assert.equal(sets, 1);
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assert.equal(obj.x ??= 2, 1);
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assert.equal(sets, 1);
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var gets = 0;
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var deep = {
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get obj() {
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gets++;
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return obj;
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},
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};
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obj.x = undefined;
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assert.equal(deep.obj.x ??= 1, 1);
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assert.equal(gets, 1);
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assert.equal(deep.obj.x ??= 2, 1);
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assert.equal(gets, 2);
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var key = 0;
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obj.x = undefined;
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assert.equal(obj[++key] ??= 1, 1);
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assert.equal(key, 1);
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key = 0;
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assert.equal(obj[++key] ??= 2, 1);
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assert.equal(key, 1);
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obj.x = undefined;
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key = 0;
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assert.equal(deep.obj[++key] ??= 1, 1);
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assert.equal(gets, 3);
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assert.equal(key, 1);
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key = 0;
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assert.equal(deep.obj[++key] ??= 2, 1);
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assert.equal(gets, 4);
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assert.equal(key, 1);
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