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LearnRemember / JAVASCRIPT



Numeric

Most of the time Javascript automatically converts to the right type. 
 
/**
 * Mathematical functions and expressions ...
 * strings are automatically converted to numbers.
 * 
 * The addition operator (+) doesn't convert strings to numbers.
 */

console.log("2" + "3"); // 23, not 5
console.log("6" / "3"); // 2

console.log(Number("2") + Number("3")); // 5
console.log(String(2)   + String(3));   // 23 - Look Here

Boolean

In Javascript, a non-empty string is always true. 
 
/**
 * In Javascript "0" is not threated as false (like in PHP)
 */

let a = "0";

if (a) {
    console.log("hello"); // hello
}






Questions and answers




Math expression that does automatic conversion?

  • a) "1" + "2"
  • b) "6" / "2"

Boolean by "0" is true in:

  • a) Javascript
  • b) PHP


References