Next.js - NavLink Component Example with Active CSS Class

This is a quick post to show how to create a custom NavLink component in Next.js that extends the built-in Link component to add the CSS className "active" when the href attribute matches the current URL. It’s based on the nav link component from a Next.js CRUD example I posted recently, for full details including a working demo see Next.js 10 - CRUD Example with React Hook Form.

Next.js Custom NavLink Component

This is the NavLink component, by default the "active" class is added when the href matches the start of the URL pathname, use the exact property to change it to an exact match with the whole URL pathname.

import { useRouter } from 'next/router';
import Link from 'next/link';
import PropTypes from 'prop-types';

export { NavLink };

NavLink.propTypes = {
    href: PropTypes.string.isRequired,
    exact: PropTypes.bool
};

NavLink.defaultProps = {
    exact: false
};

function NavLink({ href, exact, children, ...props }) {
    const { pathname } = useRouter();
    const isActive = exact ? pathname === href : pathname.startsWith(href);

    if (isActive) {
        props.className += ' active';
    }

    return (
        <Link href={href}>
            <a {...props}>
                {children}
            </a>
        </Link>
    );
}

#next.js #css #navlink

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Next.js - NavLink Component Example with Active CSS Class

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1632537859

NBB: Ad-hoc CLJS Scripting on Node.js

Nbb

Not babashka. Node.js babashka!?

Ad-hoc CLJS scripting on Node.js.

Status

Experimental. Please report issues here.

Goals and features

Nbb's main goal is to make it easy to get started with ad hoc CLJS scripting on Node.js.

Additional goals and features are:

Fast startup without relying on a custom version of Node.js.
Small artifact (current size is around 1.2MB).
First class macros.
Support building small TUI apps using Reagent.
Complement babashka with libraries from the Node.js ecosystem.

Requirements

Nbb requires Node.js v12 or newer.

How does this tool work?

CLJS code is evaluated through SCI, the same interpreter that powers babashka. Because SCI works with advanced compilation, the bundle size, especially when combined with other dependencies, is smaller than what you get with self-hosted CLJS. That makes startup faster. The trade-off is that execution is less performant and that only a subset of CLJS is available (e.g. no deftype, yet).

Usage

Install nbb from NPM:

$ npm install nbb -g

Omit -g for a local install.

Try out an expression:

$ nbb -e '(+ 1 2 3)'
6

And then install some other NPM libraries to use in the script. E.g.:

$ npm install csv-parse shelljs zx

Create a script which uses the NPM libraries:

(ns script
  (:require ["csv-parse/lib/sync$default" :as csv-parse]
            ["fs" :as fs]
            ["path" :as path]
            ["shelljs$default" :as sh]
            ["term-size$default" :as term-size]
            ["zx$default" :as zx]
            ["zx$fs" :as zxfs]
            [nbb.core :refer [*file*]]))

(prn (path/resolve "."))

(prn (term-size))

(println (count (str (fs/readFileSync *file*))))

(prn (sh/ls "."))

(prn (csv-parse "foo,bar"))

(prn (zxfs/existsSync *file*))

(zx/$ #js ["ls"])

Call the script:

$ nbb script.cljs
"/private/tmp/test-script"
#js {:columns 216, :rows 47}
510
#js ["node_modules" "package-lock.json" "package.json" "script.cljs"]
#js [#js ["foo" "bar"]]
true
$ ls
node_modules
package-lock.json
package.json
script.cljs

Macros

Nbb has first class support for macros: you can define them right inside your .cljs file, like you are used to from JVM Clojure. Consider the plet macro to make working with promises more palatable:

(defmacro plet
  [bindings & body]
  (let [binding-pairs (reverse (partition 2 bindings))
        body (cons 'do body)]
    (reduce (fn [body [sym expr]]
              (let [expr (list '.resolve 'js/Promise expr)]
                (list '.then expr (list 'clojure.core/fn (vector sym)
                                        body))))
            body
            binding-pairs)))

Using this macro we can look async code more like sync code. Consider this puppeteer example:

(-> (.launch puppeteer)
      (.then (fn [browser]
               (-> (.newPage browser)
                   (.then (fn [page]
                            (-> (.goto page "https://clojure.org")
                                (.then #(.screenshot page #js{:path "screenshot.png"}))
                                (.catch #(js/console.log %))
                                (.then #(.close browser)))))))))

Using plet this becomes:

(plet [browser (.launch puppeteer)
       page (.newPage browser)
       _ (.goto page "https://clojure.org")
       _ (-> (.screenshot page #js{:path "screenshot.png"})
             (.catch #(js/console.log %)))]
      (.close browser))

See the puppeteer example for the full code.

Since v0.0.36, nbb includes promesa which is a library to deal with promises. The above plet macro is similar to promesa.core/let.

Startup time

$ time nbb -e '(+ 1 2 3)'
6
nbb -e '(+ 1 2 3)'   0.17s  user 0.02s system 109% cpu 0.168 total

The baseline startup time for a script is about 170ms seconds on my laptop. When invoked via npx this adds another 300ms or so, so for faster startup, either use a globally installed nbb or use $(npm bin)/nbb script.cljs to bypass npx.

Dependencies

NPM dependencies

Nbb does not depend on any NPM dependencies. All NPM libraries loaded by a script are resolved relative to that script. When using the Reagent module, React is resolved in the same way as any other NPM library.

Classpath

To load .cljs files from local paths or dependencies, you can use the --classpath argument. The current dir is added to the classpath automatically. So if there is a file foo/bar.cljs relative to your current dir, then you can load it via (:require [foo.bar :as fb]). Note that nbb uses the same naming conventions for namespaces and directories as other Clojure tools: foo-bar in the namespace name becomes foo_bar in the directory name.

To load dependencies from the Clojure ecosystem, you can use the Clojure CLI or babashka to download them and produce a classpath:

$ classpath="$(clojure -A:nbb -Spath -Sdeps '{:aliases {:nbb {:replace-deps {com.github.seancorfield/honeysql {:git/tag "v2.0.0-rc5" :git/sha "01c3a55"}}}}}')"

and then feed it to the --classpath argument:

$ nbb --classpath "$classpath" -e "(require '[honey.sql :as sql]) (sql/format {:select :foo :from :bar :where [:= :baz 2]})"
["SELECT foo FROM bar WHERE baz = ?" 2]

Currently nbb only reads from directories, not jar files, so you are encouraged to use git libs. Support for .jar files will be added later.

Current file

The name of the file that is currently being executed is available via nbb.core/*file* or on the metadata of vars:

(ns foo
  (:require [nbb.core :refer [*file*]]))

(prn *file*) ;; "/private/tmp/foo.cljs"

(defn f [])
(prn (:file (meta #'f))) ;; "/private/tmp/foo.cljs"

Reagent

Nbb includes reagent.core which will be lazily loaded when required. You can use this together with ink to create a TUI application:

$ npm install ink

ink-demo.cljs:

(ns ink-demo
  (:require ["ink" :refer [render Text]]
            [reagent.core :as r]))

(defonce state (r/atom 0))

(doseq [n (range 1 11)]
  (js/setTimeout #(swap! state inc) (* n 500)))

(defn hello []
  [:> Text {:color "green"} "Hello, world! " @state])

(render (r/as-element [hello]))

Promesa

Working with callbacks and promises can become tedious. Since nbb v0.0.36 the promesa.core namespace is included with the let and do! macros. An example:

(ns prom
  (:require [promesa.core :as p]))

(defn sleep [ms]
  (js/Promise.
   (fn [resolve _]
     (js/setTimeout resolve ms))))

(defn do-stuff
  []
  (p/do!
   (println "Doing stuff which takes a while")
   (sleep 1000)
   1))

(p/let [a (do-stuff)
        b (inc a)
        c (do-stuff)
        d (+ b c)]
  (prn d))

$ nbb prom.cljs
Doing stuff which takes a while
Doing stuff which takes a while
3

Also see API docs.

Js-interop

Since nbb v0.0.75 applied-science/js-interop is available:

(ns example
  (:require [applied-science.js-interop :as j]))

(def o (j/lit {:a 1 :b 2 :c {:d 1}}))

(prn (j/select-keys o [:a :b])) ;; #js {:a 1, :b 2}
(prn (j/get-in o [:c :d])) ;; 1

Most of this library is supported in nbb, except the following:

destructuring using :syms
property access using .-x notation. In nbb, you must use keywords.

See the example of what is currently supported.

Examples

See the examples directory for small examples.

Also check out these projects built with nbb:

c64core: retrocompute aesthetics twitter bot
gallery.cljs: script to download walpapers from windowsonearth.org.
nbb-action-example: example of a Github action built with nbb.

API

See API documentation.

Migrating to shadow-cljs

See this gist on how to convert an nbb script or project to shadow-cljs.

Build

Prequisites:

babashka >= 0.4.0
Clojure CLI >= 1.10.3.933
Node.js 16.5.0 (lower version may work, but this is the one I used to build)

To build:

Clone and cd into this repo
bb release

Run bb tasks for more project-related tasks.

Download Details:
Author: borkdude
Download Link: Download The Source Code
Official Website: https://github.com/borkdude/nbb
License: EPL-1.0

#node #javascript

Graham Ssebuuma

1624150980

Next.js - NavLink Component Example with Active CSS Class

This is a quick post to show how to create a custom NavLink component in Next.js that extends the built-in Link component to add the CSS className "active" when the href attribute matches the current URL. It’s based on the nav link component from a Next.js CRUD example I posted recently, for full details including a working demo see Next.js 10 - CRUD Example with React Hook Form.

Next.js Custom NavLink Component

This is the NavLink component, by default the "active" class is added when the href matches the start of the URL pathname, use the exact property to change it to an exact match with the whole URL pathname.

import { useRouter } from 'next/router';
import Link from 'next/link';
import PropTypes from 'prop-types';

export { NavLink };

NavLink.propTypes = {
    href: PropTypes.string.isRequired,
    exact: PropTypes.bool
};

NavLink.defaultProps = {
    exact: false
};

function NavLink({ href, exact, children, ...props }) {
    const { pathname } = useRouter();
    const isActive = exact ? pathname === href : pathname.startsWith(href);

    if (isActive) {
        props.className += ' active';
    }

    return (
        <Link href={href}>
            <a {...props}>
                {children}
            </a>
        </Link>
    );
}

#next.js #css #navlink

Elvis Miranda

1578029098

7 Best Vue CSS Component for Your App

Vue CSS frameworks are great for many reasons; code is more universally understood, web applications are easier to maintain, and prototyping becomes less of an extra step and more part of the development process.

1. Tailwindcss-Vue

Tailwindcss-Vue is a library of UI components for Vue.js built using the Tailwind CSS utility-first CSS framework.

Tailwindcss-Vue

Download: https://github.com/advanced-data-machines/tailwindcss-vue/archive/master.zip

2. @zeit-ui/vue

Vue implementation for Zeit Style, originating from Zeit Design.

@zeit-ui/vue is a Vue implementation for zeit style, originating from Zeit Design. Lean more at GITHUB.

The design of the Zeit is concise and aesthetic feeling, this is an important reason for popular of Zeit. Now you can use them through the @zeit-ui/vue.

zeit-ui/vue

Download: https://github.com/zeit-ui/vue/archive/master.zip

3. CSSeffectsSnippets

Click on the animation to copy it to your clipboard

CSSeffectsSnippets

Demo: https://emilkowalski.github.io/css-effects-snippets/

Download: https://github.com/emilkowalski/css-effects-snippets/archive/master.zip

4. Vue Cirrus

A fully responsive and comprehensive CSS framework with beautiful controls and simplistic structure. Cirrus is designed to be adaptable to existing themes or when starting fresh. These are the Vue Components for this CSS framework.

Vue Cirrus

Demo: https://florianwoelki.github.io/vue-cirrus/#/

Download: https://github.com/FlorianWoelki/vue-cirrus/archive/master.zip

5. Vue CSS Modules

Seamless mapping of class names to CSS modules inside of Vue components.

Vue CSS Modules

Download: https://github.com/fjc0k/vue-css-modules/archive/master.zip

6. BG MixMaster 90 — CSS Background Grid /Pattern Generator

make a background grid (like graph paper) using only one background gradient property and ended up with this killer mix tape for making all kinds of background grids and patterns.

BG MixMaster 90