Middlewear for json-server

field.js

// Returns the value of a field/key.
// Add field=:field to url query

module.exports = (req, res, next) => {
    const _send = res.send
    res.send = function (body) {
        let field = require('url').parse(req.url, true).query['_field']
        if (field) {
            try {
                const json = JSON.parse(body)
                if (Array.isArray(json)) {
                    if (json.length === 1) {
                        return _send.call(this, JSON.stringify(json[0][field], null, '  '))
                    } else if (json.length === 0) {
                        return _send.call(this, '{}', 404)
                    }
                }
            } catch (e) { }
        }
        return _send.call(this, body)
    }
    next()
}

singular.js

// Returns an object if only one item in array
// Add singular=1 to url query

module.exports = (req, res, next) => {
    const _send = res.send
    res.send = function (body) {
        if (require('url').parse(req.url, true).query['singular']) {
            try {
                const json = JSON.parse(body)
                if (Array.isArray(json)) {
                    if (json.length === 1) {
                        return _send.call(this, JSON.stringify(json[0], null, '  '))
                    } else if (json.length === 0) {
                        return _send.call(this, '{}', 404)
                    }
                }
            } catch (e) { }
        }
        return _send.call(this, body)
    }
    next()
}