show similar postinstall messages only once per npm i, close #597,…

… thanks @remy

packages/core-js/scripts/postinstall.js

@@ -1,24 +1,49 @@
 /* eslint-disable max-len */
+var fs = require('fs');
+var os = require('os');
+var path = require('path');
 var env = process.env;
+
 var ADBLOCK = is(env.ADBLOCK);
 var CI = is(env.CI);
 var COLOR = is(env.npm_config_color);
 var DISABLE_OPENCOLLECTIVE = is(env.DISABLE_OPENCOLLECTIVE);
-var SILENT = !!~['silent', 'error', 'warn'].indexOf(env.npm_config_loglevel);
+var SILENT = ['silent', 'error', 'warn'].indexOf(env.npm_config_loglevel) !== -1;
+var MINUTE = 60 * 1000;
+
+var BANNER = '\u001B[96mThank you for using core-js (\u001B[94m https://github.com/zloirock/core-js \u001B[96m) for polyfilling JavaScript standard library!\u001B[0m\n' +
+             '\u001B[96mThe project needs your help! Please consider supporting of core-js on Open Collective or Patreon: \u001B[0m' +
+             '\u001B[96m>\u001B[94m https://opencollective.com/core-js \u001B[0m' +
+             '\u001B[96m>\u001B[94m https://www.patreon.com/zloirock \u001B[0m\n' +
+             '\u001B[96mAlso, the author of core-js (\u001B[94m https://github.com/zloirock \u001B[96m) is looking for a good job -)\u001B[0m\n';
 
 function is(it) {
   return !!it && it !== '0' && it !== 'false';
 }
 
-function log(it) {
-  // eslint-disable-next-line no-console,no-control-regex
-  console.log(COLOR ? it : it.replace(/\u001B\[\d+m/g, ''));
+function isBannerRequired() {
+  if (ADBLOCK || CI || DISABLE_OPENCOLLECTIVE || SILENT) return false;
+  var file = path.join(os.tmpdir(), 'core-js-banners');
+  var banners = [];
+  try {
+    var DELTA = Date.now() - fs.statSync(file).mtime;
+    if (DELTA >= 0 && DELTA < MINUTE * 3) {
+      banners = JSON.parse(fs.readFileSync(file, 'utf8'));
+      if (banners.indexOf(BANNER) !== -1) return false;
+    }
+  } catch (error) {
+    banners = [];
+  }
+  try {
+    banners.push(BANNER);
+    fs.writeFileSync(file, JSON.stringify(banners), 'utf8');
+  } catch (error) { /* empty */ }
+  return true;
 }
 
-if (!ADBLOCK && !CI && !DISABLE_OPENCOLLECTIVE && !SILENT) {
-  log('\u001B[96mThank you for using core-js (\u001B[94m https://github.com/zloirock/core-js \u001B[96m) for polyfilling JavaScript standard library!\u001B[0m\n');
-  log('\u001B[96mThe project needs your help! Please consider supporting of core-js on Open Collective or Patreon: \u001B[0m');
-  log('\u001B[96m>\u001B[94m https://opencollective.com/core-js \u001B[0m');
-  log('\u001B[96m>\u001B[94m https://www.patreon.com/zloirock \u001B[0m\n');
-  log('\u001B[96mAlso, the author of core-js (\u001B[94m https://github.com/zloirock \u001B[96m) is looking for a good job -)\u001B[0m\n');
+function showBanner() {
+  // eslint-disable-next-line no-console,no-control-regex
+  console.log(COLOR ? BANNER : BANNER.replace(/\u001B\[\d+m/g, ''));
 }
+
+if (isBannerRequired()) showBanner();