1. Application of Function Combination
A new function is composed of several pure functions, partial functions and Curitization functions. At the same time, data transfer is formed.
A series of functions are selected and combined to achieve the effect of public cooperation.
Code example:
function combination() {
var args = Array.prototype.slice.call(arguments);
return function(x) {
// ReducRight's specific approach allows you to view official documents
return args.reduceRight(function(res, ele) {
return ele(res);
}, x);
};
}
var arr = combination(add, spl, toUpper) // Three functions. The data of three functions are all related.
console.log(arr("tzh")); // The print result is TZH520!!!
function toUpper(str) {
return str.toUpperCase();
}
function add(str) {
return str + "!!!";
}
function spl(str) {
return str + "520";
}
Functions combine to transfer data from left to right.
2. curry
In mathematics and computer science, coritization is a technique for converting a function using multiple parameters into a series of functions using one parameter.
- Why use curry
Simplify code structure, improve system maintainability, a method, a parameter, function cohesion, reduce coupling
Code simulation coritization
function add(a, b, c, d) {
return a + b + c + d;
}
//Intercept arguments arguments and return a function
function agent(fn) {
var args = Array.prototype.slice.call(arguments, 1);
return function() {
var arr = args.concat(Array.prototype.slice.call(arguments, 0));
return fn.apply(this, arr);
};
}
// Core Idea Code of Curitization
function currie(fn, length) {
var length = length || fn.length;
return function() {
var arg_len = arguments.length;
if (length != arg_len) {
var arg = [fn].concat([].slice.call(arguments, 0));
return currie(agent.apply(this, arg), length - arg_len);
} else {
return fn.apply(this, arguments);
}
};
}
var curries = currie(add);
// Multiple forms of combined calls
var num1 = curries(1,3)(3)(4)
var num2 = curries(1,3,3)(4)
var num3 = curries(1,3)(3)(4)
console.log(num1,num2,num3);// The print results are all 13.