Amazonが出荷元になっている商品ページを表示する

amazon-lover.js

// ==UserScript==
// @name         Amazon Lover
// @namespace    https://github.com/3110
// @version      0.5
// @include      https://www.amazon.co.jp/*
// @run-at       document-start
// @description  Remove all parameters in URL and add the parameter m=AN1VRQENFRJN5 to URL
// @author       SAITO, Tetsuya <saito.tetsuya@gmail.com>
// @grant        none
// ==/UserScript==

const AMAZON_URL_BASE = 'https://www.amazon.co.jp/dp/';
const AMAZON_ONLY_PARAM = "?m=AN1VRQENFRJN5";
const AUTHOR_PAGE_REGEX = /\/(e|author)\//;
const KINDLE_REGEX = /-ebook\//;
const ASIN_REGEX = /\/([a-zA-Z0-9]{10})[/?]/;

(function() {
    'use strict';
    const url = location.href;

    if (url.indexOf(AMAZON_ONLY_PARAM) != -1) { // already added
        return;
    }
    if (url.match(KINDLE_REGEX)) { // do not add the param to Kindle page
        return;
    }
    if (url.match(AUTHOR_PAGE_REGEX)) { // do not add the param to author's page
        return;
    }

    const asin = url.match(ASIN_REGEX);
    if (asin) {
        location.href = AMAZON_URL_BASE + asin[1] + '/' + AMAZON_ONLY_PARAM;
    }
})();