FieldValue

FieldValue

Sentinel values that can be used when writing documents with set(), create() or update().

Constructor

new FieldValue()

Source:

Methods

(static) arrayRemove(…elements) → {FieldValue}

Returns a special value that can be used with set(), create() or update() that tells the server to remove the given elements from any array value that already exists on the server. All instances of each element specified will be removed from the array. If the field being modified is not already an array it will be overwritten with an empty array.

Parameters:
Name Type Attributes Description
elements * <repeatable>

The elements to remove from the array.
Source:
Example
let documentRef = firestore.doc('col/doc');

documentRef.update(
  'array', Firestore.FieldValue.arrayRemove('foo')
).then(() => {
  return documentRef.get();
}).then(doc => {
  // doc.get('array') no longer contains field 'foo'
});

(static) arrayUnion(…elements) → {FieldValue}

Returns a special value that can be used with set(), create() or update() that tells the server to union the given elements with any array value that already exists on the server. Each specified element that doesn't already exist in the array will be added to the end. If the field being modified is not already an array it will be overwritten with an array containing exactly the specified elements.

Parameters:
Name Type Attributes Description
elements * <repeatable>

The elements to union into the array.
Source:
Example
let documentRef = firestore.doc('col/doc');

documentRef.update(
  'array', Firestore.FieldValue.arrayUnion('foo')
).then(() => {
  return documentRef.get();
}).then(doc => {
  // doc.get('array') contains field 'foo'
});

(static) delete() → {FieldValue}

Returns a sentinel for use with update() or set() with {merge:true} to mark a field for deletion.

Source:
Example
let documentRef = firestore.doc('col/doc');
let data = { a: 'b', c: 'd' };

documentRef.set(data).then(() => {
  return documentRef.update({a: Firestore.FieldValue.delete()});
}).then(() => {
  // Document now only contains { c: 'd' }
});

(static) increment(n) → {FieldValue}

Returns a special value that can be used with set(), create() or update() that tells the server to increment the the field's current value by the given value.

If either current field value or the operand uses floating point precision, both values will be interpreted as floating point numbers and all arithmetic will follow IEEE 754 semantics. Otherwise, integer precision is kept and the result is capped between -2^63 and 2^63-1.

If the current field value is not of type 'number', or if the field does not yet exist, the transformation will set the field to the given value.

Parameters:
Name Type Description
n number

The value to increment by.
Source:
Example
let documentRef = firestore.doc('col/doc');

documentRef.update(
  'counter', Firestore.FieldValue.increment(1)
).then(() => {
  return documentRef.get();
}).then(doc => {
  // doc.get('counter') was incremented
});

(static) serverTimestamp() → {FieldValue}

Returns a sentinel used with set(), create() or update() to include a server-generated timestamp in the written data.

Source:
Example
let documentRef = firestore.doc('col/doc');

documentRef.set({
  time: Firestore.FieldValue.serverTimestamp()
}).then(() => {
  return documentRef.get();
}).then(doc => {
  console.log(`Server time set to ${doc.get('time')}`);
});

isEqual(other) → {boolean}

Returns true if this FieldValue is equal to the provided value.

Parameters:
Name Type Description
other *

The value to compare against.
Source:
Example
let fieldValues = [
  Firestore.FieldValue.increment(-1.0),
  Firestore.FieldValue.increment(-1),
  Firestore.FieldValue.increment(-0.0),
  Firestore.FieldValue.increment(-0),
  Firestore.FieldValue.increment(0),
  Firestore.FieldValue.increment(0.0),
  Firestore.FieldValue.increment(1),
  Firestore.FieldValue.increment(1.0)
];

let equal = 0;
for (let i = 0; i < fieldValues.length; ++i) {
  for (let j = i + 1; j < fieldValues.length; ++j) {
    if (fieldValues[i].isEqual(fieldValues[j])) {
      ++equal;
    }
  }
}
console.log(`Found ${equal} equalities.`);