WeakRef.prototype.deref()

The deref() method returns the WeakRef instance's target value, or undefined if the target value has been garbage-collected.

Syntax

js

deref()

Return value

The target value of the WeakRef, which is either an object or a non-registered symbol. Returns undefined if the value has been garbage-collected.

Description

See the Notes on WeakRefs section of the WeakRef page for some important notes.

Examples

Using deref()

See the Examples section of the WeakRef page for the complete example.

js

const tick = () => {
  // Get the element from the weak reference, if it still exists
  const element = this.ref.deref();
  if (element) {
    element.textContent = ++this.count;
  } else {
    // The element doesn't exist anymore
    console.log("The element is gone.");
    this.stop();
    this.ref = null;
  }
};

Specifications

Specification
ECMAScript Language Specification
# sec-weak-ref.prototype.deref

Browser compatibility

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See also