19Implement set(object, "a.b.c", value)

Implement set(object, path, value), like Lodash's _.set. It writes value at a nested path, creating any missing objects or arrays on the way, and returns the same object.

const config = {};
set(config, "theme.colors.primary", "#0071e3");
// { theme: { colors: { primary: "#0071e3" } } }

set(config, "plugins[0].name", "analytics");
// config.plugins is an array: [{ name: "analytics" }]

Requirements

• path is a dot string, may use [index], or is an array of keys.
• Create a missing step as an array when the next key is a number, otherwise as an object.
• Replace a primitive that is in the way with a new object or array.
• Never write through __proto__, constructor or prototype, so the function cannot pollute Object.prototype.