Set JavaScript debugger breakpoints from the console

breakpoint.js

/**
 * Utility lib for setting/unsetting JavaScript breakpoints
 *
 * Usage:
 *   breakpoint.set('globalMethodName');
 *   breakpoint.unset('globalMethodName');
 *
 *   breakpoint.set('namespacedMethodName', namespaceObject);
 *   breakpoint.unset('namespacedMethodName', namespaceObject);
 */
var breakpoint = {};

(function() {
  /**
   * Set a breakpoint on the given method
   *
   * @param methodName {String} name of method to set breakpoint on
   * @param namespace {Object} optional namespace obj; defaults to window
   */
  breakpoint.set = function(methodName, namespace) {
    namespace = namespace || window;
    var orig = namespace[methodName];

    var wrapper = function() {
      debugger;
      return orig.apply(this, arguments);
    }

    // Preserve original function reference on the
    // wrapper function itself
    wrapper._orig = orig;

    namespace[methodName] = wrapper;
  };

  /**
   * Remove a breakpoint from the given method (only works on
   * breakpoints set by this library)
   *
   * @param methodName {String} name of method to remove breakpoint from
   * @param namespace {Object} optional namespace obj; defaults to window
   */
  breakpoint.unset = function(methodName, namespace) {
    namespace = namespace || window;

    // Restore original reference (if it exists)
    if (typeof namespace[methodName]._orig === 'function') {
      namespace[methodName] = namespace[methodName]._orig;
    }
  }
})();