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'use strict';
const isOptionObject = require('is-plain-obj');
const hasOwnProperty = Object.prototype.hasOwnProperty;
const propIsEnumerable = Object.propertyIsEnumerable;
const defineProperty = (obj, name, value) => Object.defineProperty(obj, name, {
value,
writable: true,
enumerable: true,
configurable: true
});
const globalThis = this;
const defaultMergeOpts = {
concatArrays: false
};
const getEnumerableOwnPropertyKeys = value => {
const keys = [];
for (const key in value) {
if (hasOwnProperty.call(value, key)) {
keys.push(key);
}
}
/* istanbul ignore else */
if (Object.getOwnPropertySymbols) {
const symbols = Object.getOwnPropertySymbols(value);
for (let i = 0; i < symbols.length; i++) {
if (propIsEnumerable.call(value, symbols[i])) {
keys.push(symbols[i]);
}
}
}
return keys;
};
function clone(value) {
if (Array.isArray(value)) {
return cloneArray(value);
}
if (isOptionObject(value)) {
return cloneOptionObject(value);
}
return value;
}
function cloneArray(array) {
const result = array.slice(0, 0);
getEnumerableOwnPropertyKeys(array).forEach(key => {
defineProperty(result, key, clone(array[key]));
});
return result;
}
function cloneOptionObject(obj) {
const result = Object.getPrototypeOf(obj) === null ? Object.create(null) : {};
getEnumerableOwnPropertyKeys(obj).forEach(key => {
defineProperty(result, key, clone(obj[key]));
});
return result;
}
/**
* @param merged {already cloned}
* @return {cloned Object}
*/
const mergeKeys = (merged, source, keys, mergeOpts) => {
keys.forEach(key => {
// Do not recurse into prototype chain of merged
if (key in merged && merged[key] !== Object.getPrototypeOf(merged)) {
defineProperty(merged, key, merge(merged[key], source[key], mergeOpts));
} else {
defineProperty(merged, key, clone(source[key]));
}
});
return merged;
};
/**
* @param merged {already cloned}
* @return {cloned Object}
*
* see [Array.prototype.concat ( ...arguments )](http://www.ecma-international.org/ecma-262/6.0/#sec-array.prototype.concat)
*/
const concatArrays = (merged, source, mergeOpts) => {
let result = merged.slice(0, 0);
let resultIndex = 0;
[merged, source].forEach(array => {
const indices = [];
// `result.concat(array)` with cloning
for (let k = 0; k < array.length; k++) {
if (!hasOwnProperty.call(array, k)) {
continue;
}
indices.push(String(k));
if (array === merged) {
// Already cloned
defineProperty(result, resultIndex++, array[k]);
} else {
defineProperty(result, resultIndex++, clone(array[k]));
}
}
// Merge non-index keys
result = mergeKeys(result, array, getEnumerableOwnPropertyKeys(array).filter(key => {
return indices.indexOf(key) === -1;
}), mergeOpts);
});
return result;
};
/**
* @param merged {already cloned}
* @return {cloned Object}
*/
function merge(merged, source, mergeOpts) {
if (mergeOpts.concatArrays && Array.isArray(merged) && Array.isArray(source)) {
return concatArrays(merged, source, mergeOpts);
}
if (!isOptionObject(source) || !isOptionObject(merged)) {
return clone(source);
}
return mergeKeys(merged, source, getEnumerableOwnPropertyKeys(source), mergeOpts);
}
module.exports = function () {
const mergeOpts = merge(clone(defaultMergeOpts), (this !== globalThis && this) || {}, defaultMergeOpts);
let merged = {foobar: {}};
for (let i = 0; i < arguments.length; i++) {
const option = arguments[i];
if (option === undefined) {
continue;
}
if (!isOptionObject(option)) {
throw new TypeError('`' + option + '` is not an Option Object');
}
merged = merge(merged, {foobar: option}, mergeOpts);
}
return merged.foobar;
};