@flourish/sdk/lib/common.js

The Flourish SDK

const deepCopyObject = require("../common/utils/state").deepCopyObject;

function isPrimitive(entity) {
	if (entity === null) { return true; }
	return ["string", "boolean", "number"].includes(typeof entity);
}

function extendItem(extendee, extender) {
	const v = isPrimitive(extendee) ? [extendee] : extendee;
	const w = isPrimitive(extender) ? [extender] : extender;
	const CANNOT_MERGE_MESSAGE = `template.yml: cannot extend ${
		JSON.stringify(extendee, null, 2)
	} with ${
		JSON.stringify(extender, null, 2)
	}`;
	let output;

	if (Array.isArray(v)) {
		if (Array.isArray(w)) { output = v.concat(w); }
		else { throw new Error(CANNOT_MERGE_MESSAGE); }
	}
	else if (typeof v === "object") {
		// Order of Object.assign means parameters in extendee are favoured over parameters in extender
		if (typeof(w) === "object") { output = Object.assign(deepCopyObject(w), deepCopyObject(v)); }
		else { throw new Error(CANNOT_MERGE_MESSAGE); }
	}
	else { throw new Error(CANNOT_MERGE_MESSAGE); }

	return output;
}

module.exports = { extendItem };