Javascript Memoization caching function instructions_javascript skills

For example

Copy code The code is as follows:

var flower= function(){
var t=0,i=0;
for(;i<5000000;i ){
t ;
}
return t;
}

flower returns the value of t
Assume this function takes 2-3 seconds.
Through the Memoization function, when looking for the same value again, the pre-cached value is directly obtained and returned immediately;
Memoization function

Copy code The code is as follows:

var Memoize = function(fn, cache, refetch, obj){
cache = cache || {};/ /Used to cache results
return function(){
var k = arguments[1] ? Array.prototype.join.call(arguments, '__') : arguments[0];//Multiple parameters Separated by '__'
if (!(k in cache) || (refetch && cache[k] == refetch)) { //If it is not in the cache list and is equal to the given refetch value, Re-operate
cache[k] = fn.apply(obj || fn, arguments); //The obj parameter can be used to change this pointer
}
return cache[k];//Return the result
}
}

Demo:

<title> New Document </title>
[Ctrl A select all Note: If you need to introduce external Js, you need to refresh to execute

]<script> (function(){ var Memoize = function(fn, cache, refetch, obj){ cache = cache || {}; return function(){ var k = arguments[1] ? Array.prototype.join.call(arguments, '__') : arguments[0]; if( !(k in cache) && !(refetch && cache[k] == refetch)){ cache[k] = fn.apply(obj || fn, arguments); } return cache[k]; } } var test = function(){ var t=0,i=0; for(;i<12110000;i++){ t++; } return t; } var test2 = Memoize(test) alert(test2()); alert(test2()); })(); </script>