Include a novel item into the JSON string that is being received

Question

Include a novel item into the JSON string that is being received

Recently, I attempted to parse an incoming JSON string and insert a new object into it.

The method I used looked like this:

addSetting(category) {
    console.log(category.value); //Console.log = [{"meta":"","value":""}]
    category.value = JSON.parse(category.value).push({meta: "", value: ""});
    console.log(category.value); //Console.log = 2
},

However, the issue is that category.value returns 2. Shouldn't it contain two JSON objects instead? Can anyone point out where my mistake lies?

javascript json

Answer 1

Answer №1

Consider this approach:

addSetting(category) {
 category.value = JSON.parse(category.value);
 category.value.push({meta: "", value: ""});
 console.log(category.value);
}

It seems like you have misunderstood how the push() method works. The push() method actually returns the new length of the array, not the array itself.

Return value

The new length property of the object upon which the method was called.

For more details, refer to Array.prototype.push() on MDN.

Since the size of your array will be updated to 2 after pushing the new element, the following line is incorrect:

category.value = JSON.parse(category.value).push({meta: "", value: ""});

After parsing the JSON, you inadvertently assigned the return value of push to category.value.

Answer 2

Consider this approach:

addSetting(category) {
 category.value = JSON.parse(category.value);
 category.value.push({meta: "", value: ""});
 console.log(category.value);
}

It seems like you have misunderstood how the push() method works. The push() method actually returns the new length of the array, not the array itself.

Return value

The new length property of the object upon which the method was called.

For more details, refer to Array.prototype.push() on MDN.

Since the size of your array will be updated to 2 after pushing the new element, the following line is incorrect:

category.value = JSON.parse(category.value).push({meta: "", value: ""});

After parsing the JSON, you inadvertently assigned the return value of push to category.value.

Include a novel item into the JSON string that is being received

Answer №1

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