直接上代码，大家一看就明了
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<h2>call-apply-bind</h2>
<script>
'use strict'
Function.prototype.call = function () { // 纯es5写法
var targetFuc = this;
var thisArg = arguments[ 0 ]
if ( !(typeof thisArg === 'object' || typeof thisArg === 'function') ) {
throw new Error( 'type error' )
}
thisArg.nestFuc = targetFuc
var evalString = 'thisArg.nestFuc('
for ( var i = 1; i < arguments.length; i++ ) {
evalString += 'arguments[' + i + '],'
}
evalString += ')'
console.log( evalString )
return eval( evalString )
}
Function.prototype.apply = function ( thisArg, argArray ) {
if ( !(typeof thisArg === 'object' || typeof thisArg === 'function') ) {
throw new Error( 'type error' )
}
var targetFuc = this;
thisArg.nestFuc = targetFuc
var evalString = 'thisArg.nestFuc('
for ( var i = 0; i < argArray.length; i++ ) {
evalString += 'argArray[' + i + '],'
}
evalString += ')'
console.log( evalString )
return eval( evalString )
}
Function.prototype.bind = function () {
var targetFuc = this;
var slice = Array.prototype.slice
var argumentsArray = slice.call( arguments )
var thisArg = argumentsArray[ 0 ]
if ( !(typeof thisArg === 'object' || typeof thisArg === 'function') ) {
throw new Error( 'type error' )
}
return function () {
targetFuc.apply( thisArg, argumentsArray.slice(1).concat( slice.call( arguments ) ) )
}
}
var f1 = function (x,y) { console.log( this, x, y ) }
f1.call( { a: 1 }, 6, 7 )
f1.apply( { a: 1 }, [ 6, 7 ] )
var f2 = function (x,y) { console.log( this, x, y ) }
f2.bind( { b:1 }, 8, 9 )()
</script>
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