Question 304360 in Javascript Question posted in
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Javascript extract value from key-value pair in object

I’m getting the following data returned from an API:

{
    "statusCode": 200,
    "successful": true,
    "userPreferences": [
        {
            "category": "Alerts",
            "preference": {
                "ContentViolations": "true",
                "UserCommentsYou": "true",
                "UserMessagesYou": "true"
            }
        },
        {
            "category": "Display",
            "preference": {
                "DateFormat": "mm-dd-yyyy",
                "TimeFormat": "12-hour"
            }
        },
        {
            "category": "EmailList",
            "preference": {
                "ReceiveDailyDigest": "true",
                "ReceiveDealsOffers": "true"
            }
        },
        {
            "category": "Privacy",
            "preference": {
                "OtherUsersMessageYou": "true",
                "OtherUsersViewProfile": "true"
            }
        },
        {
            "category": "Units",
            "preference": {
                "Measurement": "inches",
                "Weight": "pounds"
            }
        }
    ]
}

I need to extract a preference value from a key value pair. Here is what I have:

const result = userPreferences?.filter(x => x.category === "Alerts" && x.preference["UserMessagesYou"]).map(x => x.preference.value);

It’s returning string[] | undefined but I would like it to retutn string.

In the example above I would like result to have the value "true".

Tags:

3

Answers


  1. 0

    The way I see it, I assume you want to extract one UserMessagesYou value from userPreferences array which has category Alerts right? If so, this should do it:

    const data = {
    "statusCode": 200,
    "successful": true,
    "userPreferences": [
        {
            "category": "Alerts",
            "preference": {
                "ContentViolations": "true",
                "UserCommentsYou": "true",
                "UserMessagesYou": "true"
            }
        },
        {
            "category": "Display",
            "preference": {
                "DateFormat": "mm-dd-yyyy",
                "TimeFormat": "12-hour"
            }
        },
        {
            "category": "EmailList",
            "preference": {
                "ReceiveDailyDigest": "true",
                "ReceiveDealsOffers": "true"
            }
        },
        {
            "category": "Privacy",
            "preference": {
                "OtherUsersMessageYou": "true",
                "OtherUsersViewProfile": "true"
            }
        },
        {
            "category": "Units",
            "preference": {
                "Measurement": "inches",
                "Weight": "pounds"
            }
        }
    ]
}

const result = data.userPreferences.find(userPreference => userPreference.category === "Alerts").preference.UserMessagesYou

console.log(result)
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  2. 0

    The prop preference does not have a props named value ,so it’s undefined

    const result = userPreferences?.filter(x => x.category === "Alerts" && x.preference["UserMessagesYou"]).map(x => x.preference.UserMessagesYou).join(' ');
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  3. 0

    it returns undefined because the property value does not exist within the preference object.

    (It’s in the last operation that you do within the map function: .map(x => x.preference.value))

    According to your validation, the properties you have available are:

    • ContentViolations
    • UserCommentsYou
    • UserMessagesYou

    Then you can do something like this:

    const response = {
    "statusCode": 200,
    "successful": true,
    "userPreferences": [
        {
            "category": "Alerts",
            "preference": {
                "ContentViolations": "true",
                "UserCommentsYou": "true",
                "UserMessagesYou": "true"
            }
        },
        {
            "category": "Display",
            "preference": {
                "DateFormat": "mm-dd-yyyy",
                "TimeFormat": "12-hour"
            }
        },
        {
            "category": "EmailList",
            "preference": {
                "ReceiveDailyDigest": "true",
                "ReceiveDealsOffers": "true"
            }
        },
        {
            "category": "Privacy",
            "preference": {
                "OtherUsersMessageYou": "true",
                "OtherUsersViewProfile": "true"
            }
        },
        {
            "category": "Units",
            "preference": {
                "Measurement": "inches",
                "Weight": "pounds"
            }
        }
    ]
}

const result = response.userPreferences?.filter(x => x.category === "Alerts" && x.preference["UserMessagesYou"]).map(x => x.preference.UserMessagesYou);
console.log("results ====>")
console.log(result)

    Property UserMessagesYou is accessed on the map:

    .map(x => x.preference.UserMessagesYou)

    I hope this answer has helped you.

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