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Kesion

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How to elegantly use BEM in vue3

#bem #css #vue3 #javascript

In team development, we need to formulate css naming conventions, and the BEM specification is one of the css naming conventions. Our project was developed with vue3, and I didn't find the BEM framework that I wanted on the Internet, so I wrote one myself, then I will introduce vue3-bem to you.

vue3 bem

Installation

npm i vue3-bem

Using

vue3-bem is also very easy to use. As shown below.

// .vue
import useBem from "vue3-bem";
const bem = useBem("block");
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<div :class="bem('elem', 'selected')"></div>
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.block {
  &__elem {
    &--selected {
    }
  }
}
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Api

Use useBem to set the block.

Use bem to configure elements and modfiers to return classes.

type BemFunction = function (
    e?: string | null,
    m?: string | string[] | { [key in string]: boolean }
) => string[];

function useBem(block: string) => BemFunction;

bem: BemFunction
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Tools

If you think it's too much trouble to write import for each component, you can use the plugin vite-plugin-vue3-bem so you don't need to write import vue3-bem.

Use vite-plugin-vue3-bem can help you remove import.

// .vue
<template>
  <div :class="bem('elem', 'selected')"></div>
</template>

<script lang="ts" bem-block="tip">
// do some thing
</script>

<style lang="less"> 
.tip {
  &__elem {
    &--selected {
    }
  }
}
</style>
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// vite.config.js
import ViteVue3Bem from "vite-plugin-vue3-bem";

plugins:[
    ViteVue3Bem()
]
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Type Declaration
Type declaration is required in typescript to prevent error reporting.

// env.d.ts
import "vue3-bem";
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Example

Custom block name 

<div class="tip">
    <div :class="bem("wrap")"></div>
</div>
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<script setup>
import useBem from "./useBem";
const bem = useBem('tip');
</script>
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.tip {
    &__wrap {
    }
}
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Inline modfiers 

<div :class="bem('container')">
    <div :class="bem("header")"></div>
    <div :class="bem('item',  ["selected", "highlighted"])"></div>
</div>
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<script setup>
import useBem from "./useBem";
const bem = useBem('tip');
</script>
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.tip {
    &__header {
    }
    &__item {
        &--selected {
        }
        &--highlighted {
        }
    }
}
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Conditional modfiers 

<div :class="bem('container')">
    <div :class="bem("header")"></div>
    <div :class="bem('item',  {"selected": true, "highlighted": highlighted})"></div>
</div>
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<script>
    import useBem from "./useBem";
    const bem = useBem('tip');
    const highlighted = ref(false);
</script>
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.tip {
    &__header {
    }
    &__item {
        &--selected {
        }
        &--highlighted {
        }
    }
}
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Give a star if you think it will help you.

github: vue3-bem

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