NPM WARN: [email protected] requires a peer of popper.js

Question

I have follow dependency part in package.json:

"dependencies": {
    "bootstrap": "*",
    "bootstrap-datepicker": "^1.7.1",
    "bower": "^1.8.2",
    "chosen-js": "^1.8.2",
    "datatables.net-dt": "^1.10.16",
    "jQuery-QueryBuilder": "^2.4.5",
    "jquery": "^1.4",
    "jquery-tagit": "*",
    "jquery-ui-dist": "^1.12.1",
    "prismjs": "^1.8.1",
    "qtip2": "^3.0.3",
    "multi-step-modal": 
        "git+ssh://[email protected]:2022/dependencies/multi-step-modal.git"
}

When I run npm update, I get:

[email protected] /home/opshenichnikova/NetBeansProjects/lps/public
├── [email protected] 
├── [email protected] 
├── [email protected]  (git+ssh://[email protected]:2022/dependencies/multi-step-modal.git#2f9bc29093c9939c2ba23fa18fd22001a74040d2)
├── UNMET PEER DEPENDENCY popper.js@^1.12.9
└── [email protected] 

npm WARN [email protected] requires a peer of popper.js@^1.12.9 but none was installed.

I searched for the reason and found just this: Bootstrap 4: Uncaught ReferenceError: Popper is not defined

I know that it is just warning, but I always keep my code warning-free.

Answer 1

Popper.js is not really necessary

Bootstrap 4.0.0 release contains 2 new files bootstrap.bundle.js and bootstrap.bundle.min.js which contain Popper.js inside and you really do not need it.

bootstrap.bundle.min.js is exactly Bootstrap.js + Popper.js.

In Bootstrap v4.0.0 documentation it is still mentioned that you need the file for some components

Components requiring JavaScript

• Dropdowns for displaying and positioning (also requires Popper.js)
• Tooltips and popovers for displaying and positioning (also requires Popper.js)

I have not tested it but I think it is not necessary

Solutions

You can use the NPM path 'bootstrap/dist/js/bootstrap.bundle.js'.

Or if you finally want to download Popper.js, download the version you need.

bootstrap/package.json

• Bootstrap v4.0.0 "popper.js": "^1.12.9"

• Bootstrap v4.1.1 "popper.js": "^1.14.1"

Answer 2

Bootstrap 4.0.0 requires popper, so just add "popper.js": "^1.12.9" to the package.json

For example dropdown, tooltips and popovers won't work:

https://www.codeply.com/go/CuOfa7UnUA (broken w/o popper)

Note: As of 4.1, popper.js is only required for dropdowns, tooltips and popovers.