TypeError：someobject.somefunction（…）。则不是函数

Question

I have created a utility function for getting the total size of the webtable using protractor and javascript.

this.getTableSize = function(tableElement, rowSelector, columnSelector){

        return {

            row: tableElement.all(rowSelector).count(),
            column : tableElement.all(columnSelector).count()
        }

    };

However on using the same function , i am geeting the error:

tableActions.getTableSize(table,by.css("tr"),by.css("th")).then(function(obj){
          console.log(obj);
      })

The error which i am getting is :

 TypeError: tableActions.getTableSize(...).then is not a function

Answer 1

The reason your code is failing is because you are using .then() on a function that does not return a promise .

Here's an example of a working promise :

let promise1 = new Promise( (resolve, reject) => {
    let dataReceivedSuccessfully = false; 

    if (dataReceivedSuccessfully) {
        resolve('Data Available!'); 
    }
    if (!dataReceivedSuccessfully) {
        reject('Data Corrupted!'); 
    }
}) 

promise1.then( (success) => {
    console.log(success); 
}).catch( (err) => {
    console.log(err);
})

You can use this in your code to return a resolve or reject , and then you will be able to use .then() .

https://medium.freecodecamp.org/promises-in-javascript-explained-277b98850de

Answer 2

You need to correct your method to handle the promises correctly.

I assume that tableElement.all(rowSelector).count() returns a promise else you will have to handle the callbacks;

 this.getTableSize = function (tableElement, rowSelector, columnSelector) { return Promise.all([tableElement.all(rowSelector).count(), tableElement.all(columnSelector).count()]).then(function(data) { return { row: data[0], column: data[1] } }) }; tableActions.getTableSize(table, by.css("tr"), by.css("th")).then(function (obj) { console.log(obj); }) 

Promise.all does not return the array of resolved data with bluebird promises so use.

 this.getTableSize = function (tableElement, rowSelector, columnSelector) { return ableElement.all(rowSelector).count().then(function(c) { return ableElement.all(columnSelector).count().then(function (c2) { return { row: c, column: c2 } }) }) }; tableActions.getTableSize(table, by.css("tr"), by.css("th")).then(function (obj) { console.log(obj); })