Analyzing congruent and equal in JavaScript Analyzing

Extension: 1.var a = [0] if (a) console.log (a == true); a = [2]; a == true; // print result is false  

     2. var b = 2; if (b) console.log (b == true) // print result is false

 When carried out at a reaction table A == B is determined in operation, at the contents from https://developer.mozilla.org  

	The comparison value B
		Undefined	Null	Number	String	Boolean	Object
The comparison value A	Undefined	true	true	false	false	false	IsFalsy(B)
	Null	true	true	false	false	false	IsFalsy(B)
	Number	false	false	A === B	A === ToNumber(B)	A=== ToNumber(B)	A=== ToPrimitive(B)
	String	false	false	ToNumber(A) === B	A === B	ToNumber(A) === ToNumber(B)	ToPrimitive(B) == A
	Boolean	false	false	ToNumber(A) === B	ToNumber(A) === ToNumber(B)	A === B	ToNumber(A) == ToPrimitive(B)
	Object	false	false	ToPrimitive(A) == B	ToPrimitive(A) == B	ToPrimitive(A) == ToNumber(B)	A === B

In the above table, ToNumber(A) attempts before comparing to digital conversion parameters A, which is the same as A + (unary +) effect. ToPrimitive(A)By trying to call the A A.toString() and  A.valueOf() methods to convert the parameter A to its original value (Primitive).

In general, according to the ECMAScript specification, all the objects are  undefined and  null are not equal. But most browsers allow a very narrow class of objects (ie, all pages of  document.all the object), in some cases, act as emulate  undefined role. It is equal to the operator under such a background. Thus, IsFalsy(A) the method is  true , if and only if  A follow  undefined. In all other cases, an object will not be equal to  undefined or  null.

1 thus understood that a conditional statement will be converted to Boolean function by true or false, and in the determination of a first valueOf method call, then call toString method, and then they are converted to Number The, it is converted to a 0, 1 is installed for the true, and later be converted to a 2,

2, the comparison value and Boolean, which are then converted into a numerical comparison type

so long as the comparison with the Number or Boolean type, will be converted to both sides of the equation Number

 

Congruent without any type of conversion based on the determination of whether the same