Function to replace variables in a string

replaceVars.ts

export function replaceVars(
  content: string,
  variables: { [key: string]: string }
) {
  const varRegex = /\$([a-z0-9_]*)/gi;
  let match: RegExpExecArray;

  while ((match = varRegex.exec(content)!)) {
    let [wholeVar, varName] = match;

    const varValue = variables[varName];
    if (varValue === undefined || varValue === null)
      throw new Error(`Replacement variable not found: ${wholeVar}`);

    content = content.replace(
      new RegExp(escapeSpecialRegexChars(wholeVar), "g"),
      varValue
    );
  }

  return content;
}

function escapeSpecialRegexChars(str: string) {
  return str.replace(/([$\\_])/g, "\\$1");
}