dianping/cat · error · TypeError

Function.prototype.bind - what is trying to be bound is not…

Error message

Function.prototype.bind - what is trying to be bound is not callable

What it means

html5shiv ships the MDN Function.prototype.bind polyfill for old IE. Per the (now obsolete) spec draft it throws a TypeError when .bind is called on a non-function — i.e. some code did notTheFn.bind(...) or a function reference was undefined/overwritten. In a polyfilled IE8 environment this is nearly always 'undefined is not a function' manifesting through bind on an undefined variable or host object.

Solutions

1. Inspect the stack to find which variable .bind was called on, then ensure it is defined before that code runs (script order / 404s).
2. Guard optional callbacks: if (cb && typeof cb === 'function') cb = cb.bind(ctx);
3. Add typeof checks before binding host objects in IE-specific code paths.

Example fix

// before
var handler = window.MyWidget.onEvent.bind(ctx); // MyWidget failed to load

// after
if (window.MyWidget && typeof MyWidget.onEvent === 'function') {
  var handler = MyWidget.onEvent.bind(ctx);
}

function bindSafe(fn, ctx) {
  return (typeof fn === 'function') ? fn.bind(ctx) : null;
}
var handler = bindSafe(window.MyWidget && MyWidget.onEvent, ctx);

function isCallable(v) { return typeof v === 'function'; }

When it happens

Trigger: someVar.bind(...) where someVar is undefined because the defining script failed to load or ran later; binding a non-function property (obj.method missing); feature-detection code doing X.bind on IE8 host objects that report typeof 'object'.

Common situations: Legacy IE support pages where a plugin script 404'd leaving globals undefined; third-party widgets calling .bind on optional callbacks; event handler maps referencing renamed functions.

Related errors

• can't convert to object
• Canvas is not available. If you're using IE with a…
• Object.defineProperty called on non-object
• Object.keys called on a non-object
• Property description must be an object

AI-assisted analysis of dianping/cat@e815e74d4c (2026-08-14). Data as JSON: /api/errors/f9b23623c557899e. Report an issue: GitHub.

Appendix: source

Thrown at cat-home/src/main/webapp/assets/js/uncompressed/html5shiv.js:332

  /*--------------------------------------------------------------------------*/

  // expose html5
  window.html5 = html5;

  // shiv the document
  shivDocument(document);

}(this, document));



// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function/bind#Compatibility
// IE function.bind polyfill
if (!Function.prototype.bind) {
  Function.prototype.bind = function (oThis) {
    if (typeof this !== "function") {
      // closest thing possible to the ECMAScript 5 internal IsCallable function
      throw new TypeError("Function.prototype.bind - what is trying to be bound is not callable");
    }

    var aArgs = Array.prototype.slice.call(arguments, 1), 
        fToBind = this, 
        fNOP = function () {},
        fBound = function () {
          return fToBind.apply(this instanceof fNOP && oThis
                                 ? this
                                 : oThis,
                               aArgs.concat(Array.prototype.slice.call(arguments)));
        };

    fNOP.prototype = this.prototype;
    fBound.prototype = new fNOP();

    return fBound;
  };
}

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