call,apply,bind

底层实现

call,apply,bind底层实现是C++代码，以下实现仅通过js进行模拟，并且不过度考虑边界情况

因此仅用于学习和加深理解

call实现

function rvcall(binding,...argArray){
    /* 
    处理binding为非对象或函数以及为空情况，导致设置__rvcall__时报错
    TypeError: binding.__rvcall__ is not a function
    */
    binding=binding!=null?
        Object(binding):window;
    binding.__rvcall__=this;
    var result=binding.__rvcall__(...argArray);
    delete binding.__rvcall__;
    return result;
}
Function.prototype.rvcall=rvcall;

apply实现

function rvapply(binding,argArray){
    /* 
    处理binding为非对象或函数以及为空情况，导致设置__rvapply__时报错
    TypeError: binding.__rvapply__ is not a function
    */
    binding=binding!=null?
        Object(binding):window;
    /* 
    处理args为undefined或null情况，调用扩展运算符时报错
    TypeError: argArray is not iterable (cannot read property undefined)
    */
    argArray=argArray?argArray:[];
    binding.__rvapply__=this;
    var result=binding.__rvapply__(...argArray);
    delete binding.__rvapply__;
    return result;
}
Function.prototype.rvapply=rvapply;

bind实现

function rvbind(binding,...argArray){
    /* 
    处理binding为非对象或函数以及为空情况，导致设置__rvbind__时报错
    TypeError: binding.__rvbind__ is not a function
    */
    binding=binding!=null?
        Object(binding):window;
    return (...newArgArray)=>{
        binding.__rvbind__=this;
        var result=binding.__rvbind__(...argArray,...newArgArray);
        delete binding.__rvbind__;
        return result;
    };
}
Function.prototype.rvbind=rvbind;