nealalan/js-transpiling.md

## js-transpiling.md

      
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              js-transpiling.md
            
          
    TRANSPILING

use a tool that converts your newer code into older code equivalent
ES6 adds a feature called "default parameter values." Transpiling will modify/add the code to work with ES5
Example:

// IN ES6, USE A DEFAULT VALUE
function foo(a = 2) {
	console.log( a );
}
// PRE ES6 EXPLICITLY CHECK FOR A DEFAULT VALUE AND DEFINE IT
function foo() {
	var a = arguments[0] !== (void 0) ? arguments[0] : 2;
	console.log( a );
}

A common transpiler is Traceur