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'use strict';
const Assert = require('./assert');
const internals = {};
module.exports = function (obj, chain, options) {
if (chain === false ||
chain === null ||
chain === undefined) {
return obj;
}
options = options || {};
if (typeof options === 'string') {
options = { separator: options };
}
const isChainArray = Array.isArray(chain);
Assert(!isChainArray || !options.separator, 'Separator option no valid for array-based chain');
const path = isChainArray ? chain : chain.split(options.separator || '.');
let ref = obj;
for (let i = 0; i < path.length; ++i) {
let key = path[i];
const type = options.iterables && internals.iterables(ref);
if (Array.isArray(ref) ||
type === 'set') {
const number = Number(key);
if (Number.isInteger(number)) {
key = number < 0 ? ref.length + number : number;
}
}
if (!ref ||
typeof ref === 'function' && options.functions === false || // Defaults to true
!type && ref[key] === undefined) {
Assert(!options.strict || i + 1 === path.length, 'Missing segment', key, 'in reach path ', chain);
Assert(typeof ref === 'object' || options.functions === true || typeof ref !== 'function', 'Invalid segment', key, 'in reach path ', chain);
ref = options.default;
break;
}
if (!type) {
ref = ref[key];
}
else if (type === 'set') {
ref = [...ref][key];
}
else { // type === 'map'
ref = ref.get(key);
}
}
return ref;
};
internals.iterables = function (ref) {
if (ref instanceof Set) {
return 'set';
}
if (ref instanceof Map) {
return 'map';
}
};