jkereako/replace-links.js

## replace-links.js
function getQuery() {
  const urlSearchParams = new URLSearchParams(window.location.search);
  return Object.fromEntries(urlSearchParams.entries());
}

function getAnchorTags() {
  return document.getElementsByTagName('a');
}

function getLinks() {
  return Array.from(getAnchorTags()).map(el => { return el.href; });
}

function replaceTokens(tokenizedStrings, obj) {
  const keys = Object.keys(obj);

  // Take no action if there's nothing to replace.
  if (keys.length < 1 || tokenizedStrings.length < 1) {
    return tokenizedStrings;
  }

  let processed = tokenizedStrings;

  keys.forEach(key => {
    processed = processed.map(str => {
      return str.replaceAll(`{${key}}`, obj[key]);
    })
  });

  return processed;
}

function replaceLinks() {
  const links = getLinks();

  if (links.length < 1) {
    console.error("Links not found");
    return;
  }

  const processedLinks = replaceTokens(links, getQuery());
  const anchorTags = getAnchorTags();

  // This algorithm fails otherwise
  console.assert(
    processedLinks.length === anchorTags.length,
    "Arrays are unequal in length."
  );

  // Replace links
  processedLinks.forEach((link, idx, _) => {
    anchorTags.item(idx).href = link;
  });
}

// Execute the script.
document.onreadystatechange = () => {
  if (document.readyState === "complete") {
    replaceLinks();
  }
}