面试记录>Extended get method

extended-get.js

const getx = (input, expression) => {
    if (!expression.length) return input
    expression = expression.split('.')
    const arrayMatch = expression[0].match(/(?<propName>\w+)\[(?<number>\d+)]/)
    const functionMatch = expression[0].match(/(?<propName>\w+)\((?<arguments>.*)\)/)
    if (arrayMatch) {
        return getx(input[arrayMatch.groups.propName][arrayMatch.groups.number], expression.slice(1).join('.'))
    }
    if (functionMatch) {
        const argString = functionMatch.groups.arguments.split(',')
        return getx(input[functionMatch.groups.propName](...functionMatch.groups.arguments.length ? argString.map(JSON.parse) : []), expression.slice(1).join('.'))
    }
    return getx(input[expression[0]], expression.slice(1).join('.'))
}

console.log(getx({a:{b:{c:100}}}, 'a.b.c')) /* 100 */
console.log(getx({a:{b:{c:100}}}, 'a.b.c.d')) /* undefined */
console.log(getx({a:{b:[{c:100}]}}, 'a.b[0].c')) /* 100 */
console.log(getx({a:{b:{c:function(){return {d:100}}}}} , 'a.b.c().d')) /* 100 */
console.log(getx({a:{b:{c:function(factor){return {d:100 * factor}}}}} , 'a.b.c(10).d')) /* 1000 */
console.log(getx({a:{b:{c:function(x, y){return {d: x * y}}}}} , 'a.b.c(10, 20, "a").d')) /* 200 */