+= (addition operation)
+=is jsthe addition operation of , the expression A += Brepresents: A = A + B.
as follows:
=+ (special assignment)
JavaScriptIn =+is a special assignment, the expression A =+ Bmeans: Bconvert to a number and assign to A.
=It is an assignment, +which means that the following number is a positive number; similarly, =-it means that the following number is a negative number.
usefulness
It is equivalent to telling the compiler that the value type to be assigned is a number type, and do not concatenate numbers as strings.
Example:
var a=10;
var b="abcd";
var c=+a;
console.log('c：', c);//return 10
var d=-a;
console.log('d：', d);//return -10
var f="10";
var e=+b;
var g=-f;
console.log('e：', e);//NAN
console.log('g：', g);//-10
Print result:
