Script to add a label to all cards in a trello board

trello-labeler.js

/**
 * Step 1: Create a named label
 * Step 2: Open board
 * Step 3: Open devtools console
 * Step 4: Copy and paste this whole gist into console
 * Step 5: Create an array of all cards to be renamed. For all cards: var allCards = Array.prototype.slice.call(document.querySelectorAll('.list-card'))
 * Step 6: call addLabelToCards with the list of nodes as first argument, label name as 2nd argument: addLabelToCards(allCards, 'work')
 **/

function addLabelToCards(cards, labelName) {
  'use strict';
  // Should be a real array of nodes.
  let next = cards.shift();
  if (!next) return;
  clickAndWait(next, '.js-edit-labels')
    .then(_ => clickAndWait('.js-edit-labels', '.edit-labels-pop-over'))
    .then(_ => {
      // Get just the label that matches passed in name
      let label = Array.prototype.filter.call(getAvailableLabels(), (el) => {
        return el.textContent === labelName;
      })[0];
      if(!label) {
        // This card probably already has the label applied
        return;
      }
      return clickAndWait(label, `[data-idlabel="${label.attributes['data-idlabel'].nodeValue}"].active`);
    })
    .then(_ => clickAndWait('.dialog-close-button', '!.card-detail-window'))
    .then(_ => addLabelToCards(cards, labelName));
}

function clickAndWait (clickerSelectorOrEl, elSelector) {
  let clicker = typeof clickerSelectorOrEl == 'string' ? document.querySelector(clickerSelectorOrEl) : clickerSelectorOrEl;
  let shouldGoAway = elSelector.indexOf('!') === 0;
  elSelector = elSelector.replace(/^!/, '');
  return new Promise((res) => {
    clicker.click();
    let interval = setInterval(() => {
      if (!!shouldGoAway !== !!document.querySelector(elSelector)) {
        clearInterval(interval);
        res();
      }
    }, 10);
  });
}

function getAvailableLabels() {
  return document.querySelectorAll('.edit-labels-pop-over .card-label:not(.active)');
}