Javascript: Horror Things

javascript

== horor

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1 == String(1); // true
new String(1) == new String(1); // false

0 == []; // true
0 == false; // true
[] == false; // true
[] == true; // false

console.log(0 ? "0 is true" : "0 is false"); // 0 is false

console.log([] ? "[] is true" : "[] is false"); // [] is true

0 == undefined; // false
0 == !!undefined; //true

Note

Type detach
String ‘’ ? ‘falsy’ : ‘truth’
Number 0orNaN ? ‘falsy’ : ‘truth’
Boolean false ? ‘falsy’ : ‘truth’
null ‘falsy’
undefined ‘falsy’

=== hornor

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new String(1) === new String(1); // false

NaN === NaN; // false

Array Hornor

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var a = [1,2,3];
console.log(a, 'length: ',a.length);//[1, 2, 3] "length: " 3
a[-1] = -1;
console.log(a, 'length: ',a.length);// [1, 2, 3, -1: -1] "length: " 3
a[-2] = -2;
console.log(a, 'length: ',a.length);//[1, 2, 3, -1: -1, -2: -2] "length: " 3

console.log(a[-2]);//-2