lang_option directus

index.js

export default ({ init }) => {
    // traverse the object recursively and filter all translation fields with the given translationFieldName by the specified language
    function filterTranslations(obj, languageCode, translationFieldName) {
        if(obj) Object.keys(obj).forEach(key => {
            if(key === translationFieldName && Array.isArray(obj[key])) {
                obj[key] = obj[key].find(t => !t.languages_code || t.languages_code.indexOf(languageCode) >= 0);
            }
            if (typeof obj[key] === 'object') {
                obj[key] = filterTranslations(obj[key], languageCode, translationFieldName)
            }
        });
        return obj;
    }

    init('middlewares.after', async ({ app }) => {
        app.use(function(req, res, next) {

            // just process if lang query parameter is found
            // these query params will work:
            // &lang=de
            // &lang[content]=de (if you named your translation field other than 'translations')
            if(!req.query || !req.query.lang) {
                return next()
            }

            // process body only if it's JSON
            const send = res.send
            res.send = function(body) {
                var contentType = res.get('Content-Type')
                if(contentType && contentType.includes('application/json') && body) {
                    let bodyJSON = JSON.parse(body)

                    // extract language and translation field
                    let translationField = 'translations'
                    let languageCode = req.query.lang
                    if(typeof languageCode === 'object') {
                        translationField = Object.keys(req.query.lang)[0]
                        languageCode = req.query.lang.content
                    }

                    // filter translations
                    if(typeof bodyJSON.data === 'object') {
                        bodyJSON = filterTranslations(bodyJSON, languageCode, translationField)
                        body = JSON.stringify(bodyJSON)
                    }
                }
                send.apply(this, [body])
            }
            next()
        })
    })
}