index.js

const path = require("path");

const ruleChildren = (loader) => loader.use || loader.oneOf || Array.isArray(loader.loader) && loader.loader || []

const findIndexAndRules = (rulesSource, ruleMatcher) => {
    let result = undefined
    const rules = Array.isArray(rulesSource) ? rulesSource : ruleChildren(rulesSource)
    rules.some((rule, index) => result = ruleMatcher(rule) ? {index, rules} : findIndexAndRules(ruleChildren(rule), ruleMatcher))
    return result
}

const createLoaderMatcher = (loader) => (rule) => rule.loader && rule.loader.indexOf(`${path.sep}${loader}${path.sep}`) !== -1
const fileLoaderMatcher = createLoaderMatcher('file-loader')

const addBeforeRule = (rulesSource, ruleMatcher, value) => {
    const {index, rules} = findIndexAndRules(rulesSource, ruleMatcher)
    rules.splice(index, 0, value)
}

module.exports = function (config, env) {
    const svgReactLoader = {
        test: /\.svg$/,
        loader: require.resolve('react-svg-loader')
    }

    addBeforeRule(config.module.rules, fileLoaderMatcher, svgReactLoader)

    return config
}