original.js

// https://github.com/emberjs/ember.js/blob/v3.13.0-beta.3/packages/%40ember/runloop/index.js#L226
export const bind = (...curried) => {
  assert(
    'could not find a suitable method to bind',
    (function(methodOrTarget, methodOrArg) {
      // Applies the same logic as backburner parseArgs for detecting if a method
      // is actually being passed.
      let length = arguments.length;

      if (length === 0) {
        return false;
      } else if (length === 1) {
        return typeof methodOrTarget === 'function';
      } else {
        let type = typeof methodOrArg;
        return (
          type === 'function' || // second argument is a function
          (methodOrTarget !== null && type === 'string' && methodOrArg in methodOrTarget) || // second argument is the name of a method in first argument
          typeof methodOrTarget === 'function' //first argument is a function
        );
      }
    })(...curried)
  );
  return (...args) => join(...curried.concat(args));
};

result.js

// this is what shows up in the source maps for my vendor.js
var bind = (...curried) => {
  (true && !(function (methodOrTarget, methodOrArg) {
    // Applies the same logic as backburner parseArgs for detecting if a method
    // is actually being passed.
    var length = arguments.length;

    if (length === 0) {
      return false;
    } else if (length === 1) {
      return typeof methodOrTarget === 'function';
    } else {
      var type = typeof methodOrArg;
      return type === 'function' || // second argument is a function
      methodOrTarget !== null && type === 'string' && methodOrArg in methodOrTarget || // second argument is the name of a method in first argument
      typeof methodOrTarget === 'function' //first argument is a function
      ;
    }
  }(...curried)) && (0, _debug.assert)('could not find a suitable method to bind', function (methodOrTarget, methodOrArg) {
    var length = arguments.length;

    if (length === 0) {
      return false;
    } else if (length === 1) {
      return typeof methodOrTarget === 'function';
    } else {
      var type = typeof methodOrArg;
      return type === 'function' || methodOrTarget !== null && type === 'string' && methodOrArg in methodOrTarget || typeof methodOrTarget === 'function';
    }
  }(...curried)));
  return (...args) => join(...curried.concat(args));
};