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dns.lookup() and dnsPromises.lookup() options type coercion #409
Description
Description
Since using non-proper types for options in dns.lookup() and dnsPromises.lookup() is deprecated (DEP0153) and has reached End-of-Life status in Node.js v18.0.0, we should provide a codemod to replace them.
- The codemod should ensure
familyoption is a nullish value or an integer. - The codemod should ensure
hintsoption is a nullish value or a number. - The codemod should ensure
alloption is a nullish value or a boolean. - The codemod should ensure
verbatimoption is a nullish value or a boolean. - The codemod should add explicit type conversions where needed.
Additional Information
Note that in Node.js v18.0.0, passing non-proper types for dns.lookup options now throws an ERR_INVALID_ARG_TYPE error. This change enforces proper type usage:
family: must beundefined,null, or an integer (0, 4, or 6)hints: must beundefined,null, or a numberall: must beundefined,null, or a booleanverbatim: must beundefined,null, or a boolean
The automatic type coercion was removed to prevent unexpected behavior and make the API more predictable.
Examples
Example 1: String family option
Before:
const dns = require("node:dns");
dns.lookup("example.com", { family: "4" }, (err, address) => {
console.log(address);
});After:
const dns = require("node:dns");
dns.lookup("example.com", { family: 4 }, (err, address) => {
console.log(address);
});Example 2: String all option
Before:
const dns = require("node:dns");
dns.lookup("example.com", { all: "true" }, (err, addresses) => {
console.log(addresses);
});After:
const dns = require("node:dns");
dns.lookup("example.com", { all: true }, (err, addresses) => {
console.log(addresses);
});Example 3: Number verbatim option
Before:
const dns = require("node:dns");
dns.lookup("example.com", { verbatim: 1 }, (err, address) => {
console.log(address);
});After:
const dns = require("node:dns");
dns.lookup("example.com", { verbatim: true }, (err, address) => {
console.log(address);
});Example 4: Promises API with string family
Before:
const { lookup } = require("node:dns").promises;
const address = await lookup("example.com", { family: "6" });After:
const { lookup } = require("node:dns").promises;
const address = await lookup("example.com", { family: 6 });Example 5: ESM with multiple invalid options
Before:
import { lookup } from "node:dns/promises";
const result = await lookup("example.com", {
family: "4",
all: 1,
verbatim: 0
});After:
import { lookup } from "node:dns/promises";
const result = await lookup("example.com", {
family: 4,
all: true,
verbatim: false
});Example 6: Dynamic family value
Before:
const dns = require("node:dns");
const familyStr = "4";
dns.lookup("example.com", { family: familyStr }, callback);After:
const dns = require("node:dns");
const familyStr = "4";
dns.lookup("example.com", { family: parseInt(familyStr, 10) }, callback);Example 7: Hints option with string
Before:
const dns = require("node:dns");
dns.lookup("example.com", { hints: "0" }, (err, address) => {
console.log(address);
});After:
const dns = require("node:dns");
dns.lookup("example.com", { hints: 0 }, (err, address) => {
console.log(address);
});Example 8: Valid options (no change needed)
Before:
const dns = require("node:dns");
dns.lookup("example.com", {
family: 4,
hints: dns.ADDRCONFIG,
all: false,
verbatim: true
}, (err, address) => {
console.log(address);
});After:
const dns = require("node:dns");
dns.lookup("example.com", {
family: 4,
hints: dns.ADDRCONFIG,
all: false,
verbatim: true
}, (err, address) => {
console.log(address);
});Example 9: Null and undefined values (no change needed)
Before:
const dns = require("node:dns");
dns.lookup("example.com", {
family: undefined,
all: null,
verbatim: undefined
}, callback);After:
const dns = require("node:dns");
dns.lookup("example.com", {
family: undefined,
all: null,
verbatim: undefined
}, callback);
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