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    1.2.0 • Public • Published

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    Generate one digit classname and beyond.


    Instead of using traditional css classname hashing which created unnecessary long className, using one digit classname strategy reduce className to only 1 byte.

    hashing example byte / class
    traditional hash [path][name]__[local]--[hash:base64:5] cssmain__anyLocal--YWtkd at least 8 byte
    one digit [a-Z] a 1

    Let's say if average tranditional hash has an average length of 16 and there's about 300 classes and id is used:

    // Traditional Hash
    16 * 300 // 4,800 byte used
    // one digit hash
    ( 52 * 1 ) / ( (300 - 52) * 2) // 548 byte used
    // For further explaination, please visit 'one digit hashing' section below.

    By using 1-classname, we reduce byte used by classname alone by 8.75x

    Happy Fox


    Although traditional css classname ensure that className will never be duplicated, using 'one classname' (this module) you have to make sure that className will never be duplicated by yourself. You might wanted to use traditional hash then use one className to shorten it as the following:

    import hash from '1-clasname'
    hash(`${getPathAndNameAndClassNameSomehow()}`) // cssmain__anyLocal--YWtkd => a

    Now we 100% unique one digit className and decrease bundle size.

    One digit hashing

    One digit is strategy to reduce long hash className to 1 digit only. If all one digit is used, it will use 2 digits and so on. Note: Although, theotically we can use one digit for all className (ex: emoji, ASCII character), we want to follow w3 standard for className. Which means it not really always one digit but always valid w3 standard one digit.

    This will helps reduce long className into short one thus reduce a lot of bundle size.

    The sequence can be describe as the following:

    range digit possible classname
    1-52 1 a-Z
    53-2756 2 aa-ZZ
    2757-243363 3 aaa-ZZZ
    and so on n n([a-Z])

    or illustration as example as the following:

    index 0 1 2 3 25 26 27 51 52 53 78 79 103 104 105 2755 2756 2757 143362
    character a b c d z A B Z aa ab aA aB aZ ba bb ZZ aaa aab ZZZ

    As the range goes on, it can be describe by using fibonacci sequence as the following:

    const generateLimit = (digits: number) => {
        if (digits === 0) return 0
        return 52 ** digits + generateLimit(digits - 1)
    const limit = generateLimit(digits) - (digits - 1)

    When the className is hash, it'll be stored as key in object as the following:

        [key-1]: "a",
        [key-2]: "b"
        [key-3]: "c"

    Which means when the class is called after the second time, it will not generate new className but rather using old one.

    Getting started

    Simply install with yarn or npm.

    yarn add 1-classname
    // or with npm
    npm install 1-classname

    One classname has built-in TypeScript supports which means no @types/1-classname is need.


    This library is designed to be used with localIdentName of css-loader.

    The following code demonstrate how to reduce className of .module.sass file.

    cssLoaderOptions: {
        getLocalIdent: (
        ) => {
            const filePath = loaderContext.resourcePath
            const fileBaseName = basename(filePath)
            if (/\.module\.sass$/.test(fileBaseName)) {
                const modulePathParts = filePath.split('/')
                const moduleName =
                    modulePathParts[modulePathParts.length - 2]
                return `_${oneClassName(moduleName + localName)}`
            return localName

    If you want prefix you can use template literal:

    generateLocalIdentSomehow: (string) => `${generatePrefixSomehow()}-${hash(string)}`,


    All contribution, discussion and PR is welcome.

    If you have any questions, feels free to ask at issue


    npm i 1-classname

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