type-fest - npm Package Compare versions

Comparing version 0.9.0 to 0.10.0

index.d.ts

@@ -21,1 +21,2 @@ // Basic
 export {PackageJson} from './source/package-json';
+export {TsConfigJson} from './source/tsconfig-json';

package.json

 {
 	"name": "type-fest",
-	"version": "0.9.0",
+	"version": "0.10.0",
 	"description": "A collection of essential TypeScript types",
@@ -5,0 +5,0 @@ "license": "(MIT OR CC0-1.0)",

readme.md

@@ -81,2 +81,3 @@ <div align="center">
 - [`PackageJson`](source/package-json.d.ts) - Type for [npm's `package.json` file](https://docs.npmjs.com/creating-a-package-json-file).
+- [`TsConfigJson`](source/tsconfig-json.d.ts) - Type for [TypeScript's `tsconfig.json` file](https://www.typescriptlang.org/docs/handbook/tsconfig-json.html) (TypeScript 3.7).
 
@@ -83,0 +84,0 @@ ## Declined types

source/opaque.d.ts

@@ -16,5 +16,24 @@ /**
 
-type AccountNumber = Opaque<number>;
-type AccountBalance = Opaque<number>;
+type AccountNumber = Opaque<number, 'AccountNumber'>;
+type AccountBalance = Opaque<number, 'AccountBalance'>;
 
+// The Token parameter allows the compiler to differentiate between types, whereas "unknown" will not. For example, consider the following structures:
+type ThingOne = Opaque<string>;
+type ThingTwo = Opaque<string>;
+
+// To the compiler, these types are allowed to be cast to each other as they have the same underlying type. They are both `string & { __opaque__: unknown }`.
+// To avoid this behaviour, you would instead pass the "Token" parameter, like so.
+type NewThingOne = Opaque<string, 'ThingOne'>;
+type NewThingTwo = Opaque<string, 'ThingTwo'>;
+
+// Now they're completely separate types, so the following will fail to compile.
+function createNewThingOne (): NewThingOne {
+	// As you can see, casting from a string is still allowed. However, you may not cast NewThingOne to NewThingTwo, and vice versa.
+	return 'new thing one' as NewThingOne;
+}
+
+// This will fail to compile, as they are fundamentally different types.
+const thingTwo = createNewThingOne() as NewThingTwo;
+
+// Here's another example of opaque typing.
 function createAccountNumber(): AccountNumber {
@@ -37,6 +56,12 @@ return 2 as AccountNumber;
 
-// This will compile successfully.
-accountNumber + 2;
+// This will not compile successfully.
+const newAccountNumber = accountNumber + 2;
+
+// As a side note, you can (and should) use recursive types for your opaque types to make them stronger and hopefully easier to type.
+type Person = {
+	id: Opaque<number, Person>;
+	name: string;
+};
 ```
 */
-export type Opaque<Type> = Type & {readonly __opaque__: unique symbol};
+export type Opaque<Type, Token = unknown> = Type & {readonly __opaque__: Token};

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Improved metrics

Total package byte prevSize

77464

increased by31.08%

Number of package files

20

increased by5.26%

Lines of code

1597

increased by75.3%

Number of lines in readme file

633

increased by0.16%

No dependency changes