Restrict isNumber to finite numbers

mario-campos · Copilot · web-flow · commit 46563f5d82ac · 2026-06-30T17:29:25.000-05:00
Because `NaN` and Infinity are not representable in JSON.

Co-authored-by: Copilot Autofix powered by AI &lt;175728472+Copilot@users.noreply.github.com&gt;
diff --git a/src/json/index.ts b/src/json/index.ts
@@ -30,9 +30,8 @@ export function isString(value: unknown): value is string {
   return typeof value === "string";
 }
 
-/** Asserts that `value` is a number. */
 export function isNumber(value: unknown): value is number {
-  return typeof value === "number";
+  return typeof value === "number" && Number.isFinite(value);
 }
 
 /** Asserts that `value` is either a string or undefined. */

Original file line number	Diff line number	Diff line change
`@@ -30,9 +30,8 @@ export function isString(value: unknown): value is string {`
`30`	`30`	`return typeof value === "string";`
`31`	`31`	`}`
`32`	`32`
`33`		-/** Asserts that `value` is a number. */
`34`	`33`	`export function isNumber(value: unknown): value is number {`
`35`		`- return typeof value === "number";`
	`34`	`+ return typeof value === "number" && Number.isFinite(value);`
`36`	`35`	`}`
`37`	`36`
`38`	`37`	/** Asserts that `value` is either a string or undefined. */