in src/lib/api/inline.preboot.code.ts [172:190]
export function assign(target: Object, ...optionSets: any[]): Object {
if (target === undefined || target === null) {
throw new TypeError('Cannot convert undefined or null to object');
}
const output = Object(target);
for (let index = 0; index < optionSets.length; index++) {
const source = optionSets[index];
if (source !== undefined && source !== null) {
for (const nextKey in source) {
if (source.hasOwnProperty && source.hasOwnProperty(nextKey)) {
output[nextKey] = source[nextKey];
}
}
}
}
return output;
}