I am migrating from sass to postcss. To make it easier, I am using postcss-simple-vars, which supports similar variables like sass does.
My problem is:
$size: 100px;
.class {
width: $size * 2;
}
Sass result:
.class {
width: 200px;
}
Postcss with simple vars result:
.class {
width: 100px * 2;
}
The latter seems to be invalid css code. In order to fix it, I need to use the calc() function. The problem is to find all the occurances of those calculations in my code. I have ~ 1 MB of scss...
Is there any tool (linter, compiler, etc) which would analyze my css and warn me of all the places where this needs to be taken care of?
I'm not sure if there is a pre-build plugin ready to use. But you can create a simple task in gulp and point at any error on your css file.
create your new task in your in your gulp tasks and console.log the errorInfo from your style.css file using toString() method
etc
gulp.task('styles' function() {
return gulp.src('your src ./path for your style.css ')
.on('error', function(errorInfo) {
console.log(errorInfo.toString());
this.emit('end');
})
.pipe(gulp.dest('your dest ./path four final destination path '));
});
Updating
var processors = function() {
return function(css) {
css.eachDecl('width', function(decl) {
decl.value = decl.value + ', calc({{ size }} * 2)';
});
}
};
gulp.task('css', function() {
return gulp.src('./app/assets/styles/your_style.css')
.pipe(postcss([processors]))
.pipe(gulp.dest('./app/temp/styles/'));
});
I'm trying to implement a kind of css theming in an angular 4 project. We use webpack 3 for bundling. The product is intended to be used by several companies and has to look according to their brandbooks. So we need themes.
We gonna have several builds, but we don't want to have several versions of code. All themes should remain in the same codebase. The differences are minimal: colors, icons, fonts — everything may be changed in css.
I have thought of several ways to do it, the most obvious would be to implement theming via :host-context for components and change the class of body by changing environment variable for webpack. With such method we will heve every theme inside our bundle, which is not good. Maybe there's another way?
I wonder if it is possible to have webpack load not the css file it is asked for. Instead it could look for another file by pattern, and if it exists, use that file instead of original one. Or load both files.
For example, we have a button.component.ts which imports button.component.css. If we don't tell webpack to use any theme, it works as usual. But if we do, it tries to read button.component.theme-name.css in the same directory. If that file exists, webpack imports it instead (or altogether with) the default file.
That's basically what I'm trying to do. I guess, the same mechanism would be useful for html templates in angular.
Is there a plugin to do such magic? Or maybe some sophisticated loader option? If you have another way to solve my task — feel free to drop a comment!
I created a loader which can append or replace the content of a loaded file with the content of its sibling which has a chosen theme's title in its name.
TL;DR
Create a file with loader.
Use it in webpack config.
Run webpack in THEME=<themeName> evironment.
theme-loader.js
const fs = require('fs');
const loaderUtils = require('loader-utils');
module.exports = function (mainData) {
const options = loaderUtils.getOptions(this);
let themeName = options.theme;
let mode = options.mode;
if (themeName) {
// default mode
if (!Object.keys(transform).includes(mode)) {
mode = 'replace';
}
// fileName.suffix.ext -> fileName.suffix.themeName.ext
const themeAssetPath = this.resourcePath.replace(/\.([^\.]*)$/, `.${themeName}.$1`);
const callback = this.async();
// for HMR to work
this.addDependency(themeAssetPath);
fs.readFile(themeAssetPath, 'utf8', (err, themeData) => {
if (!err) {
callback(null, transform[mode](mainData, themeData));
} else if (err.code === 'ENOENT') {
// don't worry! if it's not here then it's not needed
callback(null, mainData);
} else {
callback(err);
}
});
} else {
return mainData;
}
};
const transform = {
// concat theme file with main file
concat: (mainData, themeData) => mainData + '\n' + themeData,
// replace main file with theme file
replace: (mainData, themeData) => themeData
};
A piece of sample webpack.config.js to use this handmade loader:
resolveLoader: {
modules: [
paths.libs, // ./node_modules
paths.config // this is where our custom loader sits
]
},
module: {
rules: [
// component styles
{
test: /\.css$/,
include: path.join(paths.src, 'app'),
use: [
'raw-loader',
// search for a themed one and append it to main file if found
{
loader: 'theme-loader',
options: {
theme: process.env.THEME,
mode: 'concat'
}
}
]
},
// angular templates — search for a themed one and use it if found
{
test: /\.html$/,
use: ['raw-loader',
{
loader: 'theme-loader',
options: {
theme: process.env.THEME,
mode: 'replace'
}
}
]
}
]
}
For example, an app.component.css:
:host {
background: #f0f0f0;
color: #333333;
padding: 1rem 2rem;
display: flex;
flex-direction: column;
flex: 1;
justify-content: center;
}
nav {
/* ... */
/* something about nav element */
/* ... */
}
header {
/* ... */
/* pile of styles for header */
/* ... */
}
To implement dark theme we don't need to change all that flex and padding staff and maybe nav and header don't have their own background and font color settings. So we'll just have to override host element style. We create app.component.dark.css:
:host {
background: #222222;
color: #e0e0e0;
}
The we run webpack with environment variable THEME set to dark. The loader takes a request to process app.component.css, tries to load app.component.dark.css and voila! Themed css is appended to the end of resulting file. Because of cascade,
if multiple competing selectors have the same importance and specificity, … later rules will win over earlier rules (MDN).
For HTML we don't have such method. So we'll have to rewrite our template completely. Hopefully, you won't need to do it too often. I my case, I wanted to change like header and footer to fit the cutomer's branding demand.
This was my first attempt to create a webpack loader, please leave a comment if you see a problem with it.
I want to write an empty file even the destination file is empty.
Is it possible?
The error I get is "destination not written because minified css was empty".
I'm using grunt-contrib-cssmin module.
Only using grunt-contrib-cssmin, you cannot.
A good place to start when wondering about something specific to a piece of open source software: the source code itself — the task is only ~70 lines. From the source we can see the "error" you're getting:
if (min.length === 0) {
return grunt.log.warn('Destination not written because minified CSS was empty.');
}
You might want to look into "touching" the file. If you are familiar with *nix, you'll know that touch will create the file if it doesn't exist and not truncate it if it does. In Grunt (node.js) you might want to look into node-touch or grunt-exec.
As for your Gruntfile, you'd need only one of the following two tasks:
module.exports = function (grunt) {
var touch = require('touch');
grunt.initConfig({
'cssmin': {
'combine': {
'files': { 'path/to/output.css': ['path/to/input_one.css', 'path/to/input_two.css'] }
}
},
'exec': {
'touch': { 'command': 'touch path/to/output.css' }
}
});
grunt.loadNpmTasks('grunt-contrib-cssmin');
grunt.loadNpmTasks('grunt-exec');
grunt.registerTask('touch', touch.sync.bind(undefined, 'path/to/output.css'));
grunt.registerTask('minifycss1', ['cssmin', 'exec:touch']); // 1
grunt.registerTask('minifycss2', ['cssmin', 'touch']); // 2
};
Uses grunt-exec.
Uses node-touch.
What is the proper/accepted way to use separate stylesheets for the various views my application uses?
Currently I'm placing a link element in the view/partial's html at the top but I've been told this is bad practice even though all modern browsers support it but I can see why it's frowned upon.
The other possibility is placing the separate stylesheets in my index.html's head but I would like it to only load the stylesheet if its view is being loaded in the name of performance.
Is this bad practice since styling won't take effect until after the css is loaded form the server, leading to a quick flash of unformatted content in a slow browser? I have yet to witness this although I'm testing it locally.
Is there a way to load the CSS through the object passed to Angular's $routeProvider.when?
I know this question is old now, but after doing a ton of research on various solutions to this problem, I think I may have come up with a better solution.
UPDATE 1: Since posting this answer, I have added all of this code to a simple service that I have posted to GitHub. The repo is located here. Feel free to check it out for more info.
UPDATE 2: This answer is great if all you need is a lightweight solution for pulling in stylesheets for your routes. If you want a more complete solution for managing on-demand stylesheets throughout your application, you may want to checkout Door3's AngularCSS project. It provides much more fine-grained functionality.
In case anyone in the future is interested, here's what I came up with:
1. Create a custom directive for the <head> element:
app.directive('head', ['$rootScope','$compile',
function($rootScope, $compile){
return {
restrict: 'E',
link: function(scope, elem){
var html = '<link rel="stylesheet" ng-repeat="(routeCtrl, cssUrl) in routeStyles" ng-href="{{cssUrl}}" />';
elem.append($compile(html)(scope));
scope.routeStyles = {};
$rootScope.$on('$routeChangeStart', function (e, next, current) {
if(current && current.$$route && current.$$route.css){
if(!angular.isArray(current.$$route.css)){
current.$$route.css = [current.$$route.css];
}
angular.forEach(current.$$route.css, function(sheet){
delete scope.routeStyles[sheet];
});
}
if(next && next.$$route && next.$$route.css){
if(!angular.isArray(next.$$route.css)){
next.$$route.css = [next.$$route.css];
}
angular.forEach(next.$$route.css, function(sheet){
scope.routeStyles[sheet] = sheet;
});
}
});
}
};
}
]);
This directive does the following things:
It compiles (using $compile) an html string that creates a set of <link /> tags for every item in the scope.routeStyles object using ng-repeat and ng-href.
It appends that compiled set of <link /> elements to the <head> tag.
It then uses the $rootScope to listen for '$routeChangeStart' events. For every '$routeChangeStart' event, it grabs the "current" $$route object (the route that the user is about to leave) and removes its partial-specific css file(s) from the <head> tag. It also grabs the "next" $$route object (the route that the user is about to go to) and adds any of its partial-specific css file(s) to the <head> tag.
And the ng-repeat part of the compiled <link /> tag handles all of the adding and removing of the page-specific stylesheets based on what gets added to or removed from the scope.routeStyles object.
Note: this requires that your ng-app attribute is on the <html> element, not on <body> or anything inside of <html>.
2. Specify which stylesheets belong to which routes using the $routeProvider:
app.config(['$routeProvider', function($routeProvider){
$routeProvider
.when('/some/route/1', {
templateUrl: 'partials/partial1.html',
controller: 'Partial1Ctrl',
css: 'css/partial1.css'
})
.when('/some/route/2', {
templateUrl: 'partials/partial2.html',
controller: 'Partial2Ctrl'
})
.when('/some/route/3', {
templateUrl: 'partials/partial3.html',
controller: 'Partial3Ctrl',
css: ['css/partial3_1.css','css/partial3_2.css']
})
}]);
This config adds a custom css property to the object that is used to setup each page's route. That object gets passed to each '$routeChangeStart' event as .$$route. So when listening to the '$routeChangeStart' event, we can grab the css property that we specified and append/remove those <link /> tags as needed. Note that specifying a css property on the route is completely optional, as it was omitted from the '/some/route/2' example. If the route doesn't have a css property, the <head> directive will simply do nothing for that route. Note also that you can even have multiple page-specific stylesheets per route, as in the '/some/route/3' example above, where the css property is an array of relative paths to the stylesheets needed for that route.
3. You're done
Those two things setup everything that was needed and it does it, in my opinion, with the cleanest code possible.
#tennisgent's solution is great. However, I think is a little limited.
Modularity and Encapsulation in Angular goes beyond routes. Based on the way the web is moving towards component-based development, it is important to apply this in directives as well.
As you already know, in Angular we can include templates (structure) and controllers (behavior) in pages and components. AngularCSS enables the last missing piece: attaching stylesheets (presentation).
For a full solution I suggest using AngularCSS.
Supports Angular's ngRoute, UI Router, directives, controllers and services.
Doesn't required to have ng-app in the <html> tag. This is important when you have multiple apps running on the same page
You can customize where the stylesheets are injected: head, body, custom selector, etc...
Supports preloading, persisting and cache busting
Supports media queries and optimizes page load via matchMedia API
https://github.com/door3/angular-css
Here are some examples:
Routes
$routeProvider
.when('/page1', {
templateUrl: 'page1/page1.html',
controller: 'page1Ctrl',
/* Now you can bind css to routes */
css: 'page1/page1.css'
})
.when('/page2', {
templateUrl: 'page2/page2.html',
controller: 'page2Ctrl',
/* You can also enable features like bust cache, persist and preload */
css: {
href: 'page2/page2.css',
bustCache: true
}
})
.when('/page3', {
templateUrl: 'page3/page3.html',
controller: 'page3Ctrl',
/* This is how you can include multiple stylesheets */
css: ['page3/page3.css','page3/page3-2.css']
})
.when('/page4', {
templateUrl: 'page4/page4.html',
controller: 'page4Ctrl',
css: [
{
href: 'page4/page4.css',
persist: true
}, {
href: 'page4/page4.mobile.css',
/* Media Query support via window.matchMedia API
* This will only add the stylesheet if the breakpoint matches */
media: 'screen and (max-width : 768px)'
}, {
href: 'page4/page4.print.css',
media: 'print'
}
]
});
Directives
myApp.directive('myDirective', function () {
return {
restrict: 'E',
templateUrl: 'my-directive/my-directive.html',
css: 'my-directive/my-directive.css'
}
});
Additionally, you can use the $css service for edge cases:
myApp.controller('pageCtrl', function ($scope, $css) {
// Binds stylesheet(s) to scope create/destroy events (recommended over add/remove)
$css.bind({
href: 'my-page/my-page.css'
}, $scope);
// Simply add stylesheet(s)
$css.add('my-page/my-page.css');
// Simply remove stylesheet(s)
$css.remove(['my-page/my-page.css','my-page/my-page2.css']);
// Remove all stylesheets
$css.removeAll();
});
You can read more about AngularCSS here:
http://door3.com/insights/introducing-angularcss-css-demand-angularjs
Could append a new stylesheet to head within $routeProvider. For simplicity am using a string but could create new link element also, or create a service for stylesheets
/* check if already exists first - note ID used on link element*/
/* could also track within scope object*/
if( !angular.element('link#myViewName').length){
angular.element('head').append('<link id="myViewName" href="myViewName.css" rel="stylesheet">');
}
Biggest benefit of prelaoding in page is any background images will already exist, and less lieklyhood of FOUC
#sz3, funny enough today I had to do exactly what you were trying to achieve: 'load a specific CSS file only when a user access' a specific page. So I used the solution above.
But I am here to answer your last question: 'where exactly should I put the code. Any ideas?'
You were right including the code into the resolve, but you need to change a bit the format.
Take a look at the code below:
.when('/home', {
title:'Home - ' + siteName,
bodyClass: 'home',
templateUrl: function(params) {
return 'views/home.html';
},
controler: 'homeCtrl',
resolve: {
style : function(){
/* check if already exists first - note ID used on link element*/
/* could also track within scope object*/
if( !angular.element('link#mobile').length){
angular.element('head').append('<link id="home" href="home.css" rel="stylesheet">');
}
}
}
})
I've just tested and it's working fine, it injects the html and it loads my 'home.css' only when I hit the '/home' route.
Full explanation can be found here, but basically resolve: should get an object in the format
{
'key' : string or function()
}
You can name the 'key' anything you like - in my case I called 'style'.
Then for the value you have two options:
If it's a string, then it is an alias for a service.
If it's function, then it is injected and the return value is treated
as the dependency.
The main point here is that the code inside the function is going to be executed before before the controller is instantiated and the $routeChangeSuccess event is fired.
Hope that helps.
Awesome, thank you!! Just had to make a few adjustments to get it working with ui-router:
var app = app || angular.module('app', []);
app.directive('head', ['$rootScope', '$compile', '$state', function ($rootScope, $compile, $state) {
return {
restrict: 'E',
link: function ($scope, elem, attrs, ctrls) {
var html = '<link rel="stylesheet" ng-repeat="(routeCtrl, cssUrl) in routeStyles" ng-href="{{cssUrl}}" />';
var el = $compile(html)($scope)
elem.append(el);
$scope.routeStyles = {};
function applyStyles(state, action) {
var sheets = state ? state.css : null;
if (state.parent) {
var parentState = $state.get(state.parent)
applyStyles(parentState, action);
}
if (sheets) {
if (!Array.isArray(sheets)) {
sheets = [sheets];
}
angular.forEach(sheets, function (sheet) {
action(sheet);
});
}
}
$rootScope.$on('$stateChangeStart', function (event, toState, toParams, fromState, fromParams) {
applyStyles(fromState, function(sheet) {
delete $scope.routeStyles[sheet];
console.log('>> remove >> ', sheet);
});
applyStyles(toState, function(sheet) {
$scope.routeStyles[sheet] = sheet;
console.log('>> add >> ', sheet);
});
});
}
}
}]);
If you only need your CSS to be applied to one specific view, I'm using this handy snippet inside my controller:
$("body").addClass("mystate");
$scope.$on("$destroy", function() {
$("body").removeClass("mystate");
});
This will add a class to my body tag when the state loads, and remove it when the state is destroyed (i.e. someone changes pages). This solves my related problem of only needing CSS to be applied to one state in my application.
'use strict';
angular.module('app')
.run(
[
'$rootScope', '$state', '$stateParams',
function($rootScope, $state, $stateParams) {
$rootScope.$state = $state;
$rootScope.$stateParams = $stateParams;
}
]
)
.config(
[
'$stateProvider', '$urlRouterProvider',
function($stateProvider, $urlRouterProvider) {
$urlRouterProvider
.otherwise('/app/dashboard');
$stateProvider
.state('app', {
abstract: true,
url: '/app',
templateUrl: 'views/layout.html'
})
.state('app.dashboard', {
url: '/dashboard',
templateUrl: 'views/dashboard.html',
ncyBreadcrumb: {
label: 'Dashboard',
description: ''
},
resolve: {
deps: [
'$ocLazyLoad',
function($ocLazyLoad) {
return $ocLazyLoad.load({
serie: true,
files: [
'lib/jquery/charts/sparkline/jquery.sparkline.js',
'lib/jquery/charts/easypiechart/jquery.easypiechart.js',
'lib/jquery/charts/flot/jquery.flot.js',
'lib/jquery/charts/flot/jquery.flot.resize.js',
'lib/jquery/charts/flot/jquery.flot.pie.js',
'lib/jquery/charts/flot/jquery.flot.tooltip.js',
'lib/jquery/charts/flot/jquery.flot.orderBars.js',
'app/controllers/dashboard.js',
'app/directives/realtimechart.js'
]
});
}
]
}
})
.state('ram', {
abstract: true,
url: '/ram',
templateUrl: 'views/layout-ram.html'
})
.state('ram.dashboard', {
url: '/dashboard',
templateUrl: 'views/dashboard-ram.html',
ncyBreadcrumb: {
label: 'test'
},
resolve: {
deps: [
'$ocLazyLoad',
function($ocLazyLoad) {
return $ocLazyLoad.load({
serie: true,
files: [
'lib/jquery/charts/sparkline/jquery.sparkline.js',
'lib/jquery/charts/easypiechart/jquery.easypiechart.js',
'lib/jquery/charts/flot/jquery.flot.js',
'lib/jquery/charts/flot/jquery.flot.resize.js',
'lib/jquery/charts/flot/jquery.flot.pie.js',
'lib/jquery/charts/flot/jquery.flot.tooltip.js',
'lib/jquery/charts/flot/jquery.flot.orderBars.js',
'app/controllers/dashboard.js',
'app/directives/realtimechart.js'
]
});
}
]
}
})
);