I have a like that is like
[
{Key: 'FName', Value: 'John'},
{Key: 'LName', Value: 'Doe'},
{Key: 'Age', Value: '30'},
{Key: 'Person', Value: 'true'}
]
How is it possible to check if Person exists as a Key?
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Look into <Array>.someskara9– skara92022-07-12 22:15:33 +00:00Commented Jul 12, 2022 at 22:15
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3 Answers
Solution 1
You can use <Array>.some
I also made the function take the key you are searching in and the value that you are seeking
const arr = [
{Key: 'FName', Value: 'John'},
{Key: 'LName', Value: 'Doe'},
{Key: 'Age', Value: '30'},
{Key: 'Person', Value: 'true'}
];
function isValueInsideField(arr, fieldName, value){
return arr.some(e => e[fieldName] === value);
}
console.log(isValueInsideField(arr, 'Key', 'Person'))
console.log(isValueInsideField(arr, 'Key', '123'))Solution 2
if you want to retrieve another value from the array
const arr = [
{Key: 'FName', Value: 'John'},
{Key: 'LName', Value: 'Doe', someKey:false},
{Key: 'Age', Value: '30'},
{Key: 'Person', Value: 'true'}
];
function retriveValueIfKeyExists(arr, keyFieldName, value, valueFieldName){
// nullish concealing operator to return value even if it is falsy
// you can change it with || operator but this might lead to un wanted results
// if the value is 0 or the boolean value false
return arr.filter(e => e[keyFieldName] === value)[0]?.[valueFieldName] ?? null;
}
console.log(retriveValueIfKeyExists(arr, 'Key', 'Person', 'Value'))
console.log(retriveValueIfKeyExists(arr, 'Key', 'LName', 'someKey'))
console.log(retriveValueIfKeyExists(arr, 'Key', '123'))
Comments
Here is one way:
const vals = [
{Key: 'FName', Value: 'John'},
{Key: 'LName', Value: 'Doe'},
{Key: 'Age', Value: '30'},
{Key: 'Person', Value: 'true'}
];
const personExists = () => vals.filter(x => x.Key === 'Person').length > 0;
console.log(personExists());
Comments
There can be multiple ways to do that: Third one will return the value as well
const list = [
{Key: 'FName', Value: 'John'},
{Key: 'LName', Value: 'Doe'},
{Key: 'Age', Value: '30'},
{Key: 'Person', Value: 'true'}
];
function checkKeyClassical(key, list) {
for (let i = 0; i < list.length; i++) {
if (list[i].Key === key) {
return true;
}
}
return false;
}
function checkKeyOnlyExistence(key, list) {
return list.some(item => item.Key === key);
}
function checkKeyWithValue(key, list) {
let result = list.find(item => item.Key === key);
return result ? result.Value : false;
}
console.log(checkKeyClassical('FName', list)); // true
console.log(checkKeyOnlyExistence('FName', list)); // true
console.log(checkKeyWithValue('FName', list)); // John
console.log(checkKeyClassical('NOT_EXISTS', list)); // false
console.log(checkKeyOnlyExistence('NOT_EXISTS', list)); // false
console.log(checkKeyWithValue('NOT_EXISTS', list)); // false
