(#8649) - fix build and test warnings

updates rollup-plugin-node-resolve config fields "jsnext" and "main" to "mainFields".
replace package.json's field "jsnext:main" to modern standard "module".
replace deprecated Buffer() constructor call with equivalent Buffer.from()/Buffer.alloc().
replace module "buffer-from" with Buffer.from (obsolete, since node versions below 14 aren't supported by PouchDB).

Author: SourceR85

bin/build-module.js

@@ -74,7 +74,7 @@ function buildModule(filepath) {
         input: path.resolve(filepath, './src/index.js'),
         external: depsToSkip,
         plugins: rollupPlugins({
-          jsnext: true,
+          mainFields: ['module', 'main'],
           browser: isBrowser || forceBrowser
         })
       }).then(function (bundle) {

bin/build-pouchdb.js

@@ -76,9 +76,8 @@ function doRollup(input, browser, formatsToFiles) {
     input: addPath('pouchdb', input),
     external: external,
     plugins: rollupPlugins({
-      jsnext: true,
-      browser: browser,
-      main: false  // don't use "main"s that are CJS
+      mainFields: ["module"],
+      browser: browser
     })
   }).then(function (bundle) {
     return Promise.all(Object.keys(formatsToFiles).map(function (format) {

package.json

@@ -39,7 +39,6 @@
   },
   "dependencies": {
     "abort-controller": "3.0.0",
-    "buffer-from": "1.1.2",
     "clone-buffer": "1.0.0",
     "double-ended-queue": "2.1.0-0",
     "fetch-cookie": "0.11.0",

packages/node_modules/pouchdb-abstract-mapreduce/package.json

@@ -11,5 +11,5 @@
     "url": "https://github.com/pouchdb/pouchdb.git",
     "directory": "packages/node_modules/pouchdb-abstract-mapreduce"
   },
-  "jsnext:main": "./src/index.js"
+  "module": "./src/index.js"
 }

packages/node_modules/pouchdb-adapter-http/package.json

@@ -11,5 +11,5 @@
     "url": "https://github.com/pouchdb/pouchdb.git",
     "directory": "packages/node_modules/pouchdb-adapter-http"
   },
-  "jsnext:main": "./src/index.js"
+  "module": "./src/index.js"
 }

packages/node_modules/pouchdb-adapter-idb/package.json

@@ -11,5 +11,5 @@
     "url": "https://github.com/pouchdb/pouchdb.git",
     "directory": "packages/node_modules/pouchdb-adapter-idb"
   },
-  "jsnext:main": "./src/index.js"
+  "module": "./src/index.js"
 }

packages/node_modules/pouchdb-adapter-indexeddb/package.json

@@ -11,5 +11,5 @@
     "url": "https://github.com/pouchdb/pouchdb.git",
     "directory": "packages/node_modules/pouchdb-adapter-indexeddb"
   },
-  "jsnext:main": "./src/index.js"
+  "module": "./src/index.js"
 }

packages/node_modules/pouchdb-adapter-leveldb-core/package.json

@@ -11,7 +11,7 @@
     "url": "https://github.com/pouchdb/pouchdb.git",
     "directory": "packages/node_modules/pouchdb-adapter-leveldb-core"
   },
-  "jsnext:main": "./src/index.js",
+  "module": "./src/index.js",
   "browser": {
     "./lib/index.js": "./lib/index-browser.js",
     "./src/createEmptyBlobOrBuffer.js": "./src/createEmptyBlobOrBuffer-browser.js",

packages/node_modules/pouchdb-adapter-leveldb-core/src/index.js

@@ -2,7 +2,6 @@ import levelup from 'levelup';
 import sublevel from 'sublevel-pouchdb';
 import { obj as through } from 'through2';
 import Deque from 'double-ended-queue';
-import bufferFrom from 'buffer-from'; // ponyfill for Node <6
 import PouchDB from 'pouchdb-core';
 import {
   clone,
@@ -785,7 +784,7 @@ function LevelPouch(opts, callback) {
           type: 'put',
           prefix: stores.binaryStore,
           key: digest,
-          value: bufferFrom(data, 'binary')
+          value: Buffer.from(data, 'binary')
         }]);
         callback();
       });

packages/node_modules/pouchdb-adapter-leveldb/package.json

@@ -14,5 +14,5 @@
     "url": "https://github.com/pouchdb/pouchdb.git",
     "directory": "packages/node_modules/pouchdb-adapter-leveldb"
   },
-  "jsnext:main": "./src/index.js"
+  "module": "./src/index.js"
 }