Less mix

Do you know 2020-11-09 12:10:07
mix


In this section, we learn Less The mixture of (Mixin), Blending is a way to include or blend a set of attributes from one rule set to another . In a nutshell , In fact, mixing is a bit like functions in programming languages , In this way , Reuse can be implemented in code . If you don't understand , Let's take a look at the use of mixing through practical examples .

Ordinary Mixins

Let's take a look at the following paragraph Less Code :

.xkd{
font-size: 14px;
color: #ccc;
}
.good{
font-size: 14px;
color: #ccc;
padding: 10px;
}

It's pretty obvious ,.xkd Code in style class ,.good There are also , There are only two style classes here , If there are many selectors , Will it cause a lot of duplicate code , Can we solve this problem ?

blend Mixin Can help us solve this problem , Achieve code reuse . It's easy to use , Only need .good I quote .xkd that will do :

.xkd {
font-size: 14px;
color: #ccc;
}
.good {
.xkd;
padding: 10px;
}

Then we carry out lessc command , Will this period of Less Code compiled into CSS Code :

.con {
font-size: 14px;
color: #ccc;
}
.bot {
font-size: 14px;
color: #ccc;
padding: 10px;
}

Is this convenient , And generally to distinguish code , We will add a bracket after the referenced style class (), for example :

.xkd {
font-size: 14px;
color: #ccc;
}
.good {
font-size: 14px;
color: #ccc;
padding: 10px;
}

It's very similar to a call in a function , The same function can be called multiple times , The same style class can also be referenced multiple times .

No output Mixins

In the example above , We can see that at compile time , .xkd and .good Both style classes have been compiled to CSS Code , But sometimes it's possible that this can lead to duplication , So we may not want to .xkd The style class itself is compiled into CSS In file , How to do this .

To achieve this goal , We can define style classes , Add a pair of parentheses after the style class name () , It's like defining functions , It doesn't run if it's not called .

Example :

It's also the above paragraph Less Code , It's just that we're .xkd A pair of parentheses is added to the end :

.xkd(){
font-size: 14px;
color: #ccc;
}
.good{
.xkd();
padding: 10px;
} 

Now compile the above code , Output CSS As shown below :

.good {
font-size: 14px;
color: #ccc;
padding: 10px;
}

You can see ,.xkd() Code in is ignored at compile time , Not output .

Mixins You can also include selectors in

Example :

For example, the following code ,.banner There is also a style class .banner-p , And when we are .foot I quote .banner Style class time , Will you quote at the same time .banner-p What about the pattern of , Let's take a look :

.banner(){
font-size: 16px;
.banner-p{
color: #ffeeee;
}
}
.foot{
.banner();
}

Translate it into CSS Code :

.foot {
font-size: 16px;
}
.foot .banner-p {
color: #ffeeee;
}

After compiling from this paragraph CSS We can see from the code that , Refer to a Mixins It also reuses the properties and selectors in it .

Mixins Namespace

Less There is also the concept of a namespace in , The namespace is used to set the Mixins Grouping , Using a namespace can avoid name conflicts , And encapsulate it from the outside Mixins Group .

Example :

For example, you can use a class selector or ID Selector as a namespace , And then Mixins Put in namespace , This can avoid conflicts with other imported files , for example :

.name_space{
.xkd{
font-size: 12px;
}
}
.good{
.name_space > .xkd(); // quote
}

Translate it into CSS Code :

.name_space .xkd {
font-size: 12px;
}
.good {
font-size: 12px;
}

When we refer to styles in a namespace , Except for the above , The same effect can be achieved by using the following writing methods :

.name_space > .xkd();
.name_space.xkd;
.name_space.xkd();
.name_space .xkd;
.name_space .xkd();

!important keyword

!important Keywords are used to override specific properties . If we were Mixins Add... After the quotation !important keyword , Will be Mixins All attributes in are marked with !important .

Example :

HTML Code :

<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>Less Study (9xkd.com)</title>
<link rel="styleSheet" type="text/css" href="./index.css">
</head>
<body>
<h1> Welcome to Xiake island !</h1>
</body>
</html>

Create a Less file , The contents are as follows , Will mix !important Keyword tag :

.mixin(){
color: red;
}
h1{
color: #ccc;
.mixin() !important;
}

Translate it into CSS Code :

h1 {
color: #ccc;
color: red !important;
}

Will give priority to the use of !important Properties of keyword tags , Show the effect in the browser :

summary

In this section, we mainly study Less Medium Mixins,Mixins It's easy to use . What we need to pay attention to , If Mixins No parentheses after the name , It will compile to CSS in . If you add parentheses , Will not be compiled .

In reference to Mixins when , You can do it with or without parentheses , But it's better to add parentheses , This is to distinguish the code , Avoid confusion .

Click to see more :https://www.9xkd.com/

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