CODEWITHSUNDEEP
firebasegoogle-cloud-firestore
Eduard Januzi
Eduard Januzi

Reputation: 31

Checking Firestore property value before updating

The problem i can't seem to solve is:

I want to update a the value of a property in one of my collections lets say i have a collection "posts" and all the documents have a property(field) of votes which buy default is 1 and i want to update by one by every click.

collection doc fields

posts id1 votes: 1

Updating the value is would look something like this:

  addVote(id){
    this.postCollection.doc(id).update({
      votes: 2
    })
  }

But how would I go about if I first want to check the the value of the property and then increase it by one for each click, the firebase documentation isn't much help.

Upvotes: 0

Views: 685

Answers (1)

Doug Stevenson
Doug Stevenson

Reputation: 317467

Actually the documentation is of help here. You will need to use a transaction for changes that involve getting, modifying, and setting a value in a document.

Upvotes: 1

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