Uncaught TypeError: Can not read property 'indexOf' of undefined

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Uncaught TypeError: Can not read property 'indexOf' of undefined

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#1 by (2 votes)

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I have a somewhat strange situation, or I think I do not understand what is going on because it does not enter the if I am using the var this.searchParams.data where 3 situations happen

There's nothing

price_desc

appears

price_asc appears

Then I'm using the indexOf for the simple reason that we use ES5

But it comes as an object

{sortBy: "price_asc"}

But no matter how hard you try that when it is not defined or does not exist it does not enter if to show the products ...

    this.searchParams = window.getSearch();

    this.searchSortBy = Object.values(this.searchParams.data)[0];

    console.log('-----------1-----------');
    console.log(typeof this.searchSortBy.indexOf('price') == null);
    console.log('-----------2-----------');
    console.log(this.searchSortBy.indexOf('price') === "undefined");
    console.log('-----------3-----------');
    console.log(typeof this.searchSortBy.indexOf('price') == null);

    if (!this.searchParams.data.price && typeof this.searchSortBy.indexOf('price') == null) {
      this.getProducts();
    }

I would really appreciate the help.

javascript

asked by Marco Montoya 05.09.2018 в 21:42

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1 answer

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score 2 · Answer 1

I think you have a bad concept of how they work or how certain methods and functions are used.

To start

typeof: returns the type of the variable (operand) that you are consulting

some examples:

typeof undefined //retorna 'undefined'
typeof null //retorna 'object'

indexOf: returns the index of the first occurrence it finds and if can not find it returns -1

now indexOf can be used in Strings and Arrays and if you use it in other types of variables (say numbers, booleans) it throws you the following error

Uncaught TypeError: indexOf is not a function

now if we go to the error that throws you:

Uncaught TypeError: Can not read property 'indexOf' of undefined

this basically means that somewhere in your code you did the following:

undefined.indexOf(...)

which means that most likely the following expression is giving you undefined

this.searchSortBy // <--- esa variable no existe

EDITING

If we go to where the problem starts, it is in this line of code

this.searchSortBy = Object.values(this.searchParams.data)[0];

To make clear the use of Object.values you get a clear error if you do the following:

// estas sentencias arrojan error "Cannot convert undefined or null to object"
Object.values(null)
Object.values(undefined)

in view and considering that you do not get that error means the following

this.searchParams.data // <- esta variable si existe
// pero es probable que sea un objeto vacío, es decir
this.searchParams.data = {};
// lo que haría que
Object.values(this.searchParams.data) 
// lo anterior retornaría un arreglo vacío []
// otra opción es que la propiedad data sea como lo siguiente
this.searchParams.data = { a: undefined, b: 10};

whatever your problem is the variable this.searchParams.data