jQuery Deferred state() Method

What Is state()?

deferred.state() returns a string for the current Deferred status (since jQuery 1.7). It takes no arguments. Official docs note it is mainly useful for debugging — for example, checking whether something already resolved when you expected a reject.

deferred.state()  → String

"pending"   → not settled yet
"resolved"  → resolve() / resolveWith() ran
"rejected"  → reject() / rejectWith() ran

once settled → state never changes
prefer callbacks over polling state()

How to Use state()

Call it with no arguments; compare the returned string.

1. Hold a Deferred or its promise().
2. Call state() at a checkpoint (after a settle, in a test, while debugging).
3. Compare to "pending", "resolved", or "rejected".
4. For normal async flow, attach done/fail/then instead of looping on state().

Pseudocode

state():
    if not settled yet: return "pending"
    if resolve / resolveWith was called: return "resolved"
    if reject / rejectWith was called: return "rejected"

// after either settle:
//   state() always returns the same string

Cheat Sheet

Keep these facts handy when inspecting Deferred status.

Live Preview

Settle a Deferred different ways and watch state() change.

state() → "pending"

/* neither resolve nor reject yet */

jQuery Examples

Short, copy-ready snippets. Open the browser console, or use Try It Yourself for a live editor.

var dfd = $.Deferred();
console.log(dfd.state());  // pending

pending

var dfd = $.Deferred();
console.log(dfd.state());  // pending

dfd.resolve("ok");
console.log(dfd.state());  // resolved

pending
resolved

var dfd = $.Deferred();
dfd.reject("error");
console.log(dfd.state());  // rejected

rejected

var dfd = $.Deferred();
var p = dfd.promise();

console.log(p.state());       // pending
console.log(typeof p.resolve); // undefined

dfd.resolve("ok");
console.log(p.state());       // resolved

pending
undefined
resolved

function label(dfd) {
  var s = dfd.state();
  if (s === "pending") return "still working";
  if (s === "resolved") return "success";
  return "failed";
}

var dfd = $.Deferred();
console.log(label(dfd));  // still working
dfd.resolve();
console.log(label(dfd));  // success

still working
success

Performance Notes

A single state() read is cheap. The anti-pattern is spinning until it changes — register handlers instead.

Key Takeaways