CODEWITHSUNDEEP
javascriptarraysreactjsreact-nativeasyncstorage
Dominic
Dominic

Reputation: 95

Compare value from array of objects to string in React Native/Javascript

I'm trying to use an If statement to compare a property off of an object in an array to a String. I'm using a for-loop but for some reason, I cannot seem to trigger the conditional statement. This is the code I'm using to store the object in AsyncStorage:

onPressNext= async () => {
        if (this.state.selectedFrequency.length > 0) {
            const selectedFrequency = this.state.selectedFrequency;
            try {
                await AsyncStorage.setItem('selectedFrequency', JSON.stringify(selectedFrequency));
              } catch (error) {
                // Error saving data
              }

and this is the code I'm using to retrieve the object later:

onPressNext= async () => {

        if (this.state.selectedExclusions.length > 0) {
            try {
                const value = await AsyncStorage.getItem('selectedFrequency');
                if (value !== null) {
                  console.log(JSON.parse(value));
                  const selectedFrequency = JSON.parse(value);

                  for (let j = 0; j < selectedFrequency.length; j++) {
                    if (JSON.stringify(selectedFrequency[j].value) === 'Daily') {
                        selectedFrequency[j].splice(j, 1);
                     } else {
                        console.log(JSON.stringify(selectedFrequency[j].label));
                     }   
                 }
                }
              } catch (error) {
                // Error retrieving data
                Alert.alert(
                    error,
                    'Sorry, there was an error',
                    [
                      { text: strings.Okay, style: 'cancel' },
                    ]
                );
              }

and this is how the aray is structured: 

frequency = [
    { label: strings.Daily, value: 'Daily' },
    { label: strings.Weekly, value: 'Weekly' },
    { label: strings.Monthly, value: 'Monthly' },
    { label: strings.Every_Three_Months, value: '3 Months' },
    { label: strings.three_five_Years, value: '5 Years' },
    { label: strings.Ten_Years, value: '10 Years' }
];

What I'm expecting to happen is that if the array of objects contains an item with the string value of Daily, then that item will be removed. So the for loop goes through the array, checks the values and removes any object with the value of Daily. As mentioned below I think that the problem lies within the If statement found in the for loop.

Any help would be greatly appreciated!

Upvotes: 2

Views: 10603

Answers (3)

Ryan O&#39;Neill
Ryan O&#39;Neill

Reputation: 1800

const selectedFrequency = JSON.parse(value);
     for (let j = 0; j < selectedFrequency.length; j++) {
           if (JSON.stringify(selectedFrequency[j].value) === 'Daily')

You're looping over the characters in the selectedFrequency string that's been returned from AsyncStorage. selectedFrequency is a string, and running a for loop over it is giving you "D", "a", "i", "l", "y". Of course there is no value method on a string so every conditional is simply comparing undefined === 'Daily'

You need to loop over your frequency object instead. i.e.:

     for (let j = 0; j < frequency.length; j++) {
           if (frequency[j].value === 'Daily')

Upvotes: 2

Nimeet Shah
Nimeet Shah

Reputation: 69

JSON.stringify is used to convert a JSON to a string object. Your selectedFrequency[j].value is already a string. Therefore, you don't need to convert it.

Upvotes: 1

Ravi Raj
Ravi Raj

Reputation: 6687

I think the error is happening in your if condition

In your code selectedFrequency[j].value is already a string, but your again stringifying this string which produces result like ""Daily"" !== "Daily". Hence remove that JSON.stringify and it should work

if (selectedFrequency[j].value === 'Daily')

Upvotes: 0

Related Questions