Export labels from one repository and import them to another

export-import-github-labels.js

/**
 * EXPORT LABELS
 * 1. Copy and paste the following code into the repository browser console that you want to get the labels
 * 2. Copy the result 
 */
let labels = [];
[].slice.call(document.querySelectorAll(".js-label-link"))
.forEach(function(element) {
    labels.push({
        name: element.textContent.trim(),
        description: element.getAttribute( 'title' ),
        color: element.getAttribute("style")
            .replace("background-color:", "")
            .replace(/color:.*/,"")
            .trim()
            .replace(/^#/, "")
            .replace(/;$/, "")
            .trim(),
    })
})
console.log(JSON.stringify(labels, null, 2))

/**
 * IMPORT LABELS
 * 1. Change the JSON result to the one returned in the previous function
 * 2. Copy and paste the following code into the repository console that you want to save the labels
 */
[
  {
    "name": "example1",
    "description": "example 1",
    "color": "d73a4a"
  },
  {
    "name": "example2",
    "description": "example 2",
    "color": "dd2111"
  }
].forEach(function(label) {
  addLabel(label)
})

function updateLabel (label) {
    let flag = false;
    [].slice.call(document.querySelectorAll(".js-labels-list-item"))
    .forEach(function(element) {
        if (element.querySelector('.js-label-link').textContent.trim() === label.name) {
            flag = true
            element.querySelector('.js-edit-label').click()
            element.querySelector('.js-new-label-name-input').value = label.name
            element.querySelector('.js-new-label-color-input').value = '#' + label.color
            element.querySelector('.js-update-label .btn-primary').click()
        }
    })
    return flag
}

function addNewLabel (label) {
    document.querySelector('.js-details-target-new-label').click()
    document.querySelector('#new_label input#label-name-').value = label.name
    document.querySelector('#new_label input#label-description-').value = label.description
    document.querySelector('#new_label input#label-color-').value = '#' + label.color
    document.querySelector('#new_label .btn-primary').disabled = false
    document.querySelector('#new_label .btn-primary').click()
}

function addLabel (label) {
  if (!updateLabel(label)) addNewLabel(label)
}

Nice code, thanks Constanza