blah

blah.js

var process = require('process');
var _ = require('lodash');

const KEY_REGEX = /\w+/

function validateParams(params) {
    for (let k of Object.keys(params)) {
        if (!KEY_REGEX.test(k)) {
            return false;
        }

        if (k === 'lb') {
            return false;
        }

        if (typeof(params[k]) !== 'string') {
            return false;
        }
    }
    return true;
}

function parseInputs(args) {
    if (args.length < 3) {
        return [1, null];
    }

    let input;
    let params;
    try {
        input = require('./' + args[1]);
    } catch (err) {
        return [2, null];
    }
    try {
        params = require('./' + args[2]);
    } catch (err) {
        return [2, null];
    }

    if (!validateParams(params)) {
        return [3, null];
    }

    return [0, {input, params}];
}

function handleArray(input, params) {
    return _.map(input, (val) => {
        return executeTemplate(val, params);
    });
}

function handleObject(input, params) {
    let obj = {};
    _.each(input, (v, k) => {
        obj[k] = executeTemplate(v, params);
    })
    return obj;
}

function translate(t, params) {
    if (t === 'lb') {
        return '{';
    } else if (params[t]) {
        return params[t];
    } else {
        return '{{' + t + '}}';
    }
}

function handleString(input, params) {
    let startIdx = input.indexOf('{{');
    if (startIdx === -1) {
        return input;
    } else {
        let endIdx = input.indexOf('}}');
        if (endIdx === -1) {
            return input;
        }

        return input.slice(0, startIdx) +
            translate(input.slice(startIdx + 2, endIdx), params) +
            handleString(input.slice(endIdx + 2), params);
    }
}

function executeTemplate(input, params) {
    if (Array.isArray(input)) {
        return handleArray(input, params);
    } else if (typeof(input) === 'object' && input !== null) {
        return handleObject(input, params);
    } else if (typeof(input) === 'string') {
        return handleString(input, params);
    } else {
        return input;
    }
}

function main(args) {
    let [code, inputs] = parseInputs(args);

    if (code !== 0) {
        process.exit(code);
    }

    console.log(executeTemplate(inputs.input, inputs.params));
}

// main(process.argv);

let [code, inputs] = parseInputs(['', 'a.json', 'b.json']);
console.log(inputs)
console.log('---')
console.log(executeTemplate(inputs.input, inputs.params));
// console.log(code);