my If Else condition not working properly in React.js

Question

I am saving a record on button click but it always throwing an error.

I am including an if else condition. I have surpassed all the conditions but still my code is going to the if condition but It should not go to if condition.

code is -

my this.state.question.options value is -

[
    {
        id:3250,
        label:'good answer',
        assert:1
        position:1
    },
    {
        id:3249,
        label:'bad answer',
        assert:0
        position:2
    }
]

and I am checking if else condition as -

if (this.state.question.options.filter(o => o.assert === true).length <= 0) {
    hasError = true
    errorKey = 'add-question-modal-missing-assert-options'
}
else {
    alert("test");
}

my code should goto else part and print test as alert but it is going to if part and showing error. Why ?

I wanna show else part i.e test as alert

Your array has one value which is an object with 2 keys (0 and 1). There is no assert key, and definitely not one with a strict value of true. Then again, the array is not valid as your string values are not quoted. Please provide an MCVE. — Robby Cornelissen
– Robby Cornelissen, Commented Sep 17, 2019 at 11:06
So how can i do this ? or how can I make array for this filter or how to make filter according to this array ? — Anurag Mishra
– Anurag Mishra, Commented Sep 17, 2019 at 11:09
String values are quoted .. I am just giving you the example — Anurag Mishra
– Anurag Mishra, Commented Sep 17, 2019 at 11:09
Yeah, so give a decent example. One that doesn't leave us guessing. Having an array with only one object that has numeric property keys seems weird. A strict comparison to true when the occurring assert values are 0 and 1 also seems weird. — Robby Cornelissen
– Robby Cornelissen, Commented Sep 17, 2019 at 11:10

Leander · Accepted Answer · 2019-09-17 11:24:25Z

2

You are using the strict comparison operator (===) while comparing 2 different values. In your example, 1 is being parsed as an integer, while true is being parsed as a boolean. A strict comparison operator is used to check 2 values on equal values AND equal types.

To fix the error in your code, use a loose comparison (==) or convert the integer to a boolean by using !!1

answered Sep 17, 2019 at 11:24

Leander

1581 silver badge5 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

Yann Bertrand · Accepted Answer · 2019-09-17 11:19:16Z

0

if (this.state.question.options.filter((el) => {return !!el.assert}).length <= 0) {
    hasError = true
    errorKey = 'add-question-modal-missing-assert-options'
}
else {
    alert("test");
}

edited Sep 17, 2019 at 11:19

Yann Bertrand

3,1141 gold badge25 silver badges40 bronze badges

answered Sep 17, 2019 at 11:17

Javad Khodadadi

4081 gold badge4 silver badges13 bronze badges

Comments

Yann Bertrand · Accepted Answer · 2019-09-17 11:37:47Z

0

In JavaScript, 1 is not strictly equal to true. However, it is a good practice to use the strict equality operator ===.

You should compare o.assert with the real possible value o.assert === 1.

In terms of readability I would also consider comparing the length to 1 instead of 0:

this.state.question.options.filter(option => option.assert === 1).length < 1

answered Sep 17, 2019 at 11:37

Yann Bertrand

3,1141 gold badge25 silver badges40 bronze badges

Comments

Yann Bertrand · Accepted Answer · 2019-09-17 11:38:33Z

0

this.state.question.options value is -

[
    {
        id:3250,
        label:'good answer',
        assert:1,
        position:1
    },
    {
        id:3249,
        label:'bad answer',
        assert:0,
        position:2
    }
]

and then

if (this.state.question.options.filter(o => o.assert == true)).length <= 0) {
    hasError = true
    errorKey = 'add-question-modal-missing-assert-options'
} else {
    alert("test");
}

replace === strict type with ==

edited Sep 17, 2019 at 11:38

Yann Bertrand

3,1141 gold badge25 silver badges40 bronze badges

answered Sep 17, 2019 at 11:27

Jaisa Ram

1,76715 silver badges22 bronze badges

Comments

Dostonbek Oripjonov · Accepted Answer · 2019-09-17 11:46:53Z

0

Do u want this kind of code

if (this.state.question.options.length <= 0) {
    assert = true;
    hasError = true;
    errorKey = 'add-question-modal-missing-assert-options'
}
else {
    alert("test");
}

answered Sep 17, 2019 at 11:46

Dostonbek Oripjonov

1,6941 gold badge21 silver badges30 bronze badges

Collectives™ on Stack Overflow

my If Else condition not working properly in React.js

5 Answers 5

Comments

Comments

Comments

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

5 Answers 5

Comments

Comments

Comments

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related