Bootstrap 4 popper is undefined

问题

I'm trying to get a dropdown going and whenever I click on the button I get TypeError: popper is undefined.

I tried importing the bundle instead of bootstrap

// import "bootstrap";
import 'bootstrap/dist/js/bootstrap.bundle.js';

I tried importing jquery first

import "jquery";
import "bootstrap";

I tried importing popper as well

import "popper.js/dist/umd/popper.min.js";
import "jquery";
import "bootstrap";

I also tried including popper from a CDN before any other scripts

<script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.12.9/umd/popper.min.js"></script>

And I tried just about any combination of imports mentioned above, still getting this error, even when I can access Popper in the console.

<div class="d-flex justify-content-between dropdown luri-eayq">
   <a href="/messages" class="btn btn-light flex-1 py-3 rounded-0">
      Messages
   </a>
   <a href="/phonebook" class="btn btn-light flex-1 py-3 rounded-0">
      Phonebook
   </a>
   <button id="dd" class="btn btn-light flex-1 py-3 rounded-0 mt-0" data-toggle="dropwdown">
      More
   </button>
   <div class="dropdown-menu"><a class="dropdown-item" href="/problems">Problems</a></div>
</div>

I then call the following, since it's a dynamically generated element

$("#dd").dropdown();

My question is different than the suggested, because I explain that I already tried all of the suggested solutions and none worked.

回答1:

Solution:

You can use the bundled bootstrap popper by importing

<script src="/js/bootstrap.bundle.min.js"></script>

See the documentation here.

Or use the UDM Version of popper, see details below.

Steps to use popper

I like package managers. So here goes:

npm init

Just say yes to everything..

npm install bootstrap --save
npm install jquery --save
npm install popper.js --save

I created two folders js and css with an index.html file as follows:

 index.html
 package.json
 package-lock.json
 |_ js
 |_ css
 |_ node_modules
     |_ bootstrap
       |_ dist
     |_ jquery
       |_ dist
     |_ popper.js
       |_ dist
          |_udm
          |_esm

I then copied the files from the dist folder in various libraries located in node_modules to the css and js folders. With the exception of popper, use the popper.js file or popper.min.js file located in the dist/udm folder

The contents of the index.html file is as follows:

<!DOCTYPE html>
<html class="no-js" lang="en">
    <head>
        <title>Popper Test</title>
        <link rel="stylesheet" href="/css/bootstrap.min.css">
    </head>

    <body>

            <div class="dropdown">
                    <button class="btn btn-secondary dropdown-toggle" type="button" id="dropdownMenuButton" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
                      Dropdown button
                    </button>
                    <div class="dropdown-menu" aria-labelledby="dropdownMenuButton">
                      <a class="dropdown-item" href="#">Action</a>
                      <a class="dropdown-item" href="#">Another action</a>
                      <a class="dropdown-item" href="#">Something else here</a>
                    </div>
                  </div>

        <script src="/js/jquery.min.js"></script>
        <script src="/js/popper.js"></script>
        <script src="/js/bootstrap.min.js"></script>
        <!-- <script src="/js/bootstrap.bundle.min.js"></script> -->
    </body>
</html>

To run the example I used: http-server found here By running

npm install http-server -g
http-server

If you have not used the UDM version then Opening chrome and going to http://127.0.0.1:8080. Brings up my page, hitting F12 and then trying to press the dropdown fails with the error message:

bootstrap.min.js:6 Uncaught TypeError: Bootstrap's dropdowns require Popper.js (https://popper.js.org/)
    at c.t.toggle (bootstrap.min.js:6)
    at HTMLButtonElement.<anonymous> (bootstrap.min.js:6)
    at Function.each (jquery.min.js:2)
    at w.fn.init.each (jquery.min.js:2)
    at w.fn.init.c._jQueryInterface [as dropdown] (bootstrap.min.js:6)
    at HTMLButtonElement.<anonymous> (bootstrap.min.js:6)
    at HTMLDocument.dispatch (jquery.min.js:2)
    at HTMLDocument.y.handle (jquery.min.js:2)

Either use the UDM version described above or the bundled bootstrap version by switching from:

<script src="/js/jquery.min.js"></script>
<script src="/js/popper.js"></script>
<script src="/js/bootstrap.min.js"></script>
<!-- <script src="/js/bootstrap.bundle.min.js"></script> -->

to :

<script src="/js/jquery.min.js"></script>
<!-- <script src="/js/popper.js"></script> -->
<!-- <script src="/js/bootstrap.min.js"></script>-->
<script src="/js/bootstrap.bundle.min.js"></script>

Works.

Versions implemented were:

bootstrap: 4.2.1
jquery: 3.3.1
popper.js: 1.14.6

回答2:

try to import this order:

jquery
popper
bootstrap

for example:

<script src="js/jquery.min.js"></script>
<script src="js/popper.min.js"></script>
<script src="js/bootstrap.min.js"></script>

来源：https://stackoverflow.com/questions/54397838/bootstrap-4-popper-is-undefined

标签

javascript

html

bootstrap-4

popper.js