✨ add node/prefer-promises rules (fixes #157, fixes #158)

Author: mysticatea

.eslintrc.js

@@ -58,5 +58,16 @@ module.exports = {
  ],
  },
  },
+ {
+ files: ["**/rules/prefer-promises/*.js"],
+ rules: {
+ "@mysticatea/eslint-plugin/require-meta-docs-url": [
+ "error",
+ {
+ pattern: `https://github.com/mysticatea/eslint-plugin-node/blob/v${version}/docs/rules/prefer-promises/{{name}}.md`,
+ },
+ ],
+ },
+ },
  ],
 }

README.md

@@ -92,6 +92,8 @@ $ npm install --save-dev eslint eslint-plugin-node
 | [node/prefer-global/text-encoder](./docs/rules/prefer-global/text-encoder.md) | enforce either `TextEncoder` or `require("util").TextEncoder` | |
 | [node/prefer-global/url-search-params](./docs/rules/prefer-global/url-search-params.md) | enforce either `URLSearchParams` or `require("url").URLSearchParams` | |
 | [node/prefer-global/url](./docs/rules/prefer-global/url.md) | enforce either `URL` or `require("url").URL` | |
+| [node/prefer-promises/dns](./docs/rules/prefer-promises/dns.md) | enforce `require("dns").promises` | |
+| [node/prefer-promises/fs](./docs/rules/prefer-promises/fs.md) | enforce `require("fs").promises` | |
 
 ### Deprecated rules
 

docs/rules/prefer-promises/dns.md

@@ -0,0 +1,54 @@
+# enforce `require("dns").promises` (prefer-promises/dns)
+
+Since Node.js v11.14.0, `require("dns").promises` API has been stable.
+Promise API and `async`/`await` syntax will make code more readable than callback API.
+
+## Rule Details
+
+This rule disallows callback API in favor of promise API.
+
+Examples of :-1: **incorrect** code for this rule:
+
+```js
+/*eslint node/prefer-promises/dns: [error]*/
+const dns = require("dns")
+
+function lookup(hostname) {
+ dns.lookup(hostname, (error, address, family) => {
+ //...
+ })
+}
+```
+
+```js
+/*eslint node/prefer-promises/dns: [error]*/
+import dns from "dns"
+
+function lookup(hostname) {
+ dns.lookup(hostname, (error, address, family) => {
+ //...
+ })
+}
+```
+
+Examples of :+1: **correct** code for this rule:
+
+```js
+/*eslint node/prefer-promises/dns: [error]*/
+const { promises: dns } = require("dns")
+
+async function lookup(hostname) {
+ const { address, family } = await dns.lookup(hostname)
+ //...
+}
+```
+
+```js
+/*eslint node/prefer-promises/dns: [error]*/
+import { promises as dns } from "dns"
+
+async function lookup(hostname) {
+ const { address, family } = await dns.lookup(hostname)
+ //...
+}
+```

docs/rules/prefer-promises/fs.md

@@ -0,0 +1,54 @@
+# enforce `require("fs").promises` (prefer-promises/fs)
+
+Since Node.js v11.14.0, `require("fs").promises` API has been stable.
+Promise API and `async`/`await` syntax will make code more readable than callback API.
+
+## Rule Details
+
+This rule disallows callback API in favor of promise API.
+
+Examples of :-1: **incorrect** code for this rule:
+
+```js
+/*eslint node/prefer-promises/fs: [error]*/
+const fs = require("fs")
+
+function readData(filePath) {
+ fs.readFile(filePath, "utf8", (error, content) => {
+ //...
+ })
+}
+```
+
+```js
+/*eslint node/prefer-promises/fs: [error]*/
+import fs from "fs"
+
+function readData(filePath) {
+ fs.readFile(filePath, "utf8", (error, content) => {
+ //...
+ })
+}
+```
+
+Examples of :+1: **correct** code for this rule:
+
+```js
+/*eslint node/prefer-promises/fs: [error]*/
+const { promises: fs } = require("fs")
+
+async function readData(filePath) {
+ const content = await fs.readFile(filePath, "utf8")
+ //...
+}
+```
+
+```js
+/*eslint node/prefer-promises/fs: [error]*/
+import { promises as fs } from "fs"
+
+async function readData(filePath) {
+ const content = await fs.readFile(filePath, "utf8")
+ //...
+}
+```

lib/index.js

@@ -30,6 +30,8 @@ module.exports = {
  "prefer-global/text-encoder": require("./rules/prefer-global/text-encoder"),
  "prefer-global/url-search-params": require("./rules/prefer-global/url-search-params"),
  "prefer-global/url": require("./rules/prefer-global/url"),
+ "prefer-promises/dns": require("./rules/prefer-promises/dns"),
+ "prefer-promises/fs": require("./rules/prefer-promises/fs"),
  "process-exit-as-throw": require("./rules/process-exit-as-throw"),
  shebang: require("./rules/shebang"),
 

lib/rules/prefer-promises/dns.js

@@ -0,0 +1,74 @@
+/**
+ * @author Toru Nagashima
+ * See LICENSE file in root directory for full license.
+ */
+"use strict"
+
+const { CALL, CONSTRUCT, ReferenceTracker } = require("eslint-utils")
+
+const trackMap = {
+ dns: {
+ lookup: { [CALL]: true },
+ lookupService: { [CALL]: true },
+ Resolver: { [CONSTRUCT]: true },
+ getServers: { [CALL]: true },
+ resolve: { [CALL]: true },
+ resolve4: { [CALL]: true },
+ resolve6: { [CALL]: true },
+ resolveAny: { [CALL]: true },
+ resolveCname: { [CALL]: true },
+ resolveMx: { [CALL]: true },
+ resolveNaptr: { [CALL]: true },
+ resolveNs: { [CALL]: true },
+ resolvePtr: { [CALL]: true },
+ resolveSoa: { [CALL]: true },
+ resolveSrv: { [CALL]: true },
+ resolveTxt: { [CALL]: true },
+ reverse: { [CALL]: true },
+ setServers: { [CALL]: true },
+ },
+}
+
+module.exports = {
+ meta: {
+ docs: {
+ description: 'enforce `require("dns").promises`',
+ category: "Stylistic Issues",
+ recommended: false,
+ url:
+ "https://github.com/mysticatea/eslint-plugin-node/blob/v8.0.1/docs/rules/prefer-promises/dns.md",
+ },
+ fixable: null,
+ messages: {
+ preferPromises: "Use 'dns.promises.{{name}}()' instead.",
+ preferPromisesNew: "Use 'new dns.promises.{{name}}()' instead.",
+ },
+ schema: [],
+ type: "suggestion",
+ },
+
+ create(context) {
+ return {
+ "Program:exit"() {
+ const scope = context.getScope()
+ const tracker = new ReferenceTracker(scope, { mode: "legacy" })
+ const references = [
+ ...tracker.iterateCjsReferences(trackMap),
+ ...tracker.iterateEsmReferences(trackMap),
+ ]
+
+ for (const { node, path } of references) {
+ const name = path[path.length - 1]
+ const isClass = name[0] === name[0].toUpperCase()
+ context.report({
+ node,
+ messageId: isClass
+ ? "preferPromisesNew"
+ : "preferPromises",
+ data: { name },
+ })
+ }
+ },
+ }
+ },
+}

lib/rules/prefer-promises/fs.js

@@ -0,0 +1,76 @@
+/**
+ * @author Toru Nagashima
+ * See LICENSE file in root directory for full license.
+ */
+"use strict"
+
+const { CALL, ReferenceTracker } = require("eslint-utils")
+
+const trackMap = {
+ fs: {
+ access: { [CALL]: true },
+ copyFile: { [CALL]: true },
+ open: { [CALL]: true },
+ rename: { [CALL]: true },
+ truncate: { [CALL]: true },
+ rmdir: { [CALL]: true },
+ mkdir: { [CALL]: true },
+ readdir: { [CALL]: true },
+ readlink: { [CALL]: true },
+ symlink: { [CALL]: true },
+ lstat: { [CALL]: true },
+ stat: { [CALL]: true },
+ link: { [CALL]: true },
+ unlink: { [CALL]: true },
+ chmod: { [CALL]: true },
+ lchmod: { [CALL]: true },
+ lchown: { [CALL]: true },
+ chown: { [CALL]: true },
+ utimes: { [CALL]: true },
+ realpath: { [CALL]: true },
+ mkdtemp: { [CALL]: true },
+ writeFile: { [CALL]: true },
+ appendFile: { [CALL]: true },
+ readFile: { [CALL]: true },
+ },
+}
+
+module.exports = {
+ meta: {
+ docs: {
+ description: 'enforce `require("fs").promises`',
+ category: "Stylistic Issues",
+ recommended: false,
+ url:
+ "https://github.com/mysticatea/eslint-plugin-node/blob/v8.0.1/docs/rules/prefer-promises/fs.md",
+ },
+ fixable: null,
+ messages: {
+ preferPromises: "Use 'fs.promises.{{name}}()' instead.",
+ },
+ schema: [],
+ type: "suggestion",
+ },
+
+ create(context) {
+ return {
+ "Program:exit"() {
+ const scope = context.getScope()
+ const tracker = new ReferenceTracker(scope, { mode: "legacy" })
+ const references = [
+ ...tracker.iterateCjsReferences(trackMap),
+ ...tracker.iterateEsmReferences(trackMap),
+ ]
+
+ for (const { node, path } of references) {
+ const name = path[path.length - 1]
+ context.report({
+ node,
+ messageId: "preferPromises",
+ data: { name },
+ })
+ }
+ },
+ }
+ },
+}