Javascript Objects: Find the first nested object with values that are null

Question

I have an api that returns a nested object of this form:

obj: {
    nestedobj1: {
        name: 'a',
        prop2: 'b',
        prop3: 'c',
        prop4: 'd'
    },
    nestedobj2: {
        name: 'a',
        prop2: 'b',
        prop3: 'c',
        prop4: 'd'
    },
    nestedobj3: {
        name: null,
        prop2: null,
        prop3: null,
        prop4: null
    },
    nestedobj4: {
        name: null,
        prop2: null,
        prop3: null,
        prop4: null
    },
// and so on up to 15 nested objects whose internal properties are null
}

These nested objects are supposed to hold a row of table data. When the user enters the details for the fields, the inputs need to be saved in one of the nested object for which the name value is null. How do I achieve this in javascript?

Answer 1

If I understand correctly, you want to extract the first a key/value entry from obj where the value object itself contains any null values.

One way to achieve that would be to:

1. extract the key/value entries of obj via Object.entries() and then,
2. filter the entries array for any where the entry value object contains one or more null values (this can be done using Object.values() and .some() - see snippet below),
3. reconstruct any entries that pass the previous filtering step to original object form
4. return the first matching result, if any

This could be expressed in code as:

 const obj={nestedobj1:{name:'a',prop2:'b',prop3:'c',prop4:'d'},nestedobj2:{name:'a',prop2:'b',prop3:'c',prop4:'d'},nestedobj3:{name:null,prop2:null,prop3:null,prop4:null},nestedobj4:{name:null,prop2:null,prop3:null,prop4:null}}; /* Pluck first value from result array, if any */ const [ firstObjectWithNull ] = Object.entries(obj) /* Filter/find any key/value entries from state object where object values have any nulls */ .filter(entry => { const [key, object] = entry; const objectValues = Object.values(object); /* With "some()", find the first entry where the values of the object have a null */ return objectValues.some(value => value === null); }) .map(entry => { /* Reconstuct any fiiltered entries to key/value objects */ const [key, object] = entry; return { [key] : object }; }); console.log(firstObjectWithNull);