JavaScript function return Object as JSON

Question

In need to add an Object to my Firestore database. It only takes JSON objects. However I also want to exclude some fields of my object to not get send to my database.

So I added a function that should return a JSON like this:

export class Entry {

date: number;
timeStart: number;
timeEnd: number;
entry: EntryData;

// To be excluded from database
selected: boolean;

constructor(date: number, timeStart: number, timeEnd: number, entry: EntryData) {
    this.date = date;
    this.timeStart = timeStart;
    this.timeEnd = timeEnd;
    this.entry = entry;
}

toJSON() {
    return {date: this.date, timeStart: this.timeStart, timeEnd: this.timeEnd, entry: JSON.parse(JSON.stringify(this.entry)) };
}
}

However when I do console.log(entry.toJSON()) I get this:

workday.service.ts:122 ƒ () {
        return { date: this.date, timeStart: this.timeStart, timeEnd: this.timeEnd, entry: JSON.parse(JSON.stringify(this.entry)) };
    }

I want to use the function like this:

this.employeeRef.collection('Entries').add(entry.toJSON);

But that doesn't work. It works like this:

    this.employeeRef.collection('Entries').add(JSON.parse(JSON.stringify(entry)));

But this way the selected field is not excluded from the database.

Any Ideas? Note that I'm using TypeScript (with Angular) but I think thats a pure JavaScript problem.

Your toJSON function returns an object. You really need to learn the difference between JSON and JavaScript objects so that you can ask a clear question. — Quentin
– Quentin, Commented Aug 20, 2018 at 14:43
I guess you actually did console.log(entry.toJSON) instead of console.log(entry.toJSON()) — Jonas Wilms
– Jonas Wilms, Commented Aug 20, 2018 at 14:47

Jonas Wilms · Accepted Answer · 2018-08-20 14:56:31Z

1

You probably want to use a getter:

 get toJSON() {
   return {date: this.date, timeStart: this.timeStart, timeEnd: this.timeEnd, entry: JSON.parse(JSON.stringify(this.entry)) };
 }

edited Aug 20, 2018 at 14:56

answered Aug 20, 2018 at 14:46

Jonas Wilms

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2 Comments

Marie Over a year ago

You may want to include some documentation (e.g. developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/…) with this answer. A nooby javascript user may not know what a getter is

Jonas Over a year ago

Damn now I feel stupid, I forgot the () as you mentioned. Also I had to change the method a little bit, I awserded below

Jonas · Accepted Answer · 2018-08-20 14:59:00Z

0

This seems to work:

toJSON() {
    return {date: this.date, timeStart: this.timeStart, timeEnd: this.timeEnd, entry: JSON.parse(JSON.stringify(this.entry)) };
}

I can use it like this:

his.employeeRef.collection('Entries').add(entry.toJSON());

answered Aug 20, 2018 at 14:59

Jonas

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