Parsing and replacing marked tags with values from an object

parse-and-replace-string-variables.ts

const dataObject = {
	firstName: "John",
	lastName: "Doe",
	// age // the parse fn will attempt to access this variable which does not exist
	fullName: "John Doe",
};

type DataObjectInput = Record<string, string | number | null>;

function parseStringWithTemplateLiteralVariables(rawString = "", variables: DataObjectInput = {}) {
	return rawString
		.replace(/\$\{(.*?)\}/g, (_, p1) => {
			if (p1 in variables) {
				return `${variables[p1]}`;
			}
			return "${" + p1 + "}"; // controls what is returned when the dataObject doesn't contain the key (i.e. p1)
		})
		.trim();
}

function parseStringWithPercentageTagVariables(rawString = "", variables: DataObjectInput = {}) {
	return rawString
		.replace(/%%(.*?)%%/g, (_, p1) => {
			if (p1 in variables) {
				return `${variables[p1]}`;
			}
			return `%%${p1}%%`; // controls what is returned when the dataObject doesn't contain the key (i.e. p1)
		})
		.trim();
}

const templateLiteralString = "${firstName} ${lastName} ${age} is a person.";

console.log("------------------------\ntemplate literals\n------------------------");
console.log("raw: ", templateLiteralString);
console.log("parsed: ", parseStringWithTemplateLiteralVariables(templateLiteralString, dataObject)); // output is "John Doe ${age} is a person."

const doublePercentageString = "%%firstName%% %%lastName%% %%age%% is a person.";

console.log("\n------------------------\nDouble %% wrappers\n------------------------");
console.log("raw: ", doublePercentageString);
console.log("parsed: ", parseStringWithPercentageTagVariables(doublePercentageString, dataObject)); // output is "John Doe %%age%% is a person."