javascript - Creating a simplified underscore _.invoke -


i trying create underscore's _.invoke function. can't figure out why keep getting typeerror, cannot read property 'sort' of undefined. assume refers array being passed function, can log each array in collection, don't know why undefined in being thrown up.

function each(collection, iteratee, context) {    let    let bounditeratee = iteratee.bind(context)    if (array.isarray(collection)) {      (i = 0; < collection.length; i++) {        bounditeratee(collection[i], i, context)      }    } else {      (i in collection) {        if (collection.hasownproperty(i)) {          bounditeratee(collection[i], i, collection);        }      }    }    return collection  }    function map(collection, iteratee, context) {    let result = []    let formula = function(element, index) {      result.push(iteratee(element, index, context))    }    each(collection, formula, context)    return result  }    function invoke(collection, methodname) {    let args = array.prototype.slice.call(arguments, 2)    let formula = function(array, index) {      //console.log(array) --> returns arrays in collection...      return methodname.apply(array, args)    }    return map(collection, formula)  }    function sortit(array) {    return array.sort()  }    console.log(invoke([    [3, 1, 2],    [7, 6, 9]  ], sortit))

depending on you're trying achieve, can either replace sortit function with:

function sortit() { return this.sort(); } // since apply arrays context function

or replace 

return methodname.apply(array, args);

with

return methodname(array);

neither ideal, though.

also, please apply() method.


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