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

.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 },
+                    })
+                }
+            },
+        }
+    },
+}