JavaScript you really don’t understand

integer

parseInt(a,10); //Before

Math.floor(a); //Before

a>>0; //Before

~~a; //After

a|0; //After
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rounded

Math.round(a); //Before

a+. 5|0; //After
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Built-in value

undefined; //Before

void 0; / / After that fast

0[0]; / / After, a little slow
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/ / internal value

Infinity;

1/0;
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Boolean short notation

true; //Before

!0; //After
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// Boolean short

false; //Before

!1; //After
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You don’t understand series