node-data-modeling/src/json-stringify-pre-replacer/index.js

"use strict";

module.exports = function jsonStringifyPreReplacer(data, replacer = ((key, value) => value)) {
	function stringifyPiece(parent, key, node, level) {
		let replacedNode = replacer(key, node);

		let serializedNode;

		if (replacedNode != null && typeof replacedNode.toJSON === "function") {
			serializedNode = replacedNode.toJSON();
		} else {
			serializedNode = replacedNode;
		}

		if (serializedNode === undefined) {
			return;
		} else if (typeof serializedNode !== "object" || serializedNode === null) {
			return JSON.stringify(serializedNode);
		} else if (Array.isArray(serializedNode)) {
			let stringifiedItems = serializedNode.map((item, i) => {
				let stringifiedItem = stringifyPiece(serializedNode, i, item, level + 1);

				if (stringifiedItem === undefined) {
					return null;
				} else {
					return stringifiedItem;
				}
			});

			return `[${stringifiedItems.join(",")}]`;
		} else {
			let stringifiedItems = Object.entries(serializedNode).map(([key, value]) => {
				let stringifiedValue = stringifyPiece(serializedNode, key, value, level + 1);

				if (stringifiedValue !== undefined) {
					return `${JSON.stringify(key)}:${stringifiedValue}`;
				} else {
					return undefined;
				}
			}).filter((item) => {
				return (item !== undefined);
			});

			return `{${stringifiedItems.join(",")}}`;
		}
	}

	return stringifyPiece({"": data}, "", data, 0);
};