merge.js•1.19 kB
var clone = require('./clone');
module.exports = merge;
function typesMatch(a, b) {
return (typeof a === typeof b) && (Array.isArray(a) === Array.isArray(b));
}
/**
* A deep merge of the source based on the target.
* @param {Object} source [description]
* @param {Object} target [description]
* @return {Object} [description]
*/
function merge(source, target, result) {
if (result === undefined) {
result = clone(source);
}
// merge missing values from the target to the source
Object.getOwnPropertyNames(target).forEach(function (key) {
if (source[key] === undefined) {
result[key] = target[key];
}
});
Object.getOwnPropertyNames(source).forEach(function (key) {
var value = source[key];
if (target[key] && typesMatch(value, target[key])) {
// merge empty values
if (value === '') {
result[key] = target[key];
}
if (Array.isArray(value)) {
if (value.length === 0 && target[key].length) {
result[key] = target[key].slice(0);
}
} else if (typeof value === 'object') {
result[key] = merge(value, target[key]);
}
}
});
return result;
}