fix: Fixed nix build.

flake.lock

@@ -1,20 +1,44 @@
 {
   "nodes": {
-    "nixpkgs": {
+    "bp": {
+      "inputs": {
+        "nixpkgs": [
+          "nixpkgs"
+        ]
+      },
       "locked": {
-        "lastModified": 1680665430,
-        "narHash": "sha256-MTVhTukwza1Jlq2gECITZPFnhROmylP2uv3O3cSqQCE=",
-        "path": "/nix/store/0acd255ca1v8m4xcg5wjhi9pgmx7q2s5-source",
-        "rev": "5233fd2ba76a3accb5aaa999c00509a11fd0793c",
-        "type": "path"
+        "lastModified": 1685037876,
+        "narHash": "sha256-ccqZqY6wUFot0ewyNKQUrMR6IEliGza+pjKoSVMXIeM=",
+        "owner": "sbrow",
+        "repo": "nix-npm-buildpackage",
+        "rev": "8a834ccbadee80c0ee313494f1ee95b0775b3f16",
+        "type": "github"
       },
       "original": {
-        "id": "nixpkgs",
-        "type": "indirect"
+        "owner": "sbrow",
+        "repo": "nix-npm-buildpackage",
+        "type": "github"
+      }
+    },
+    "nixpkgs": {
+      "locked": {
+        "lastModified": 1684936879,
+        "narHash": "sha256-BOSq/QiX7MDs8tUnAt4+nYTJctgYkzVSNL95qlfMYeM=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "99fe1b870522d6ee3e692c2b6e663d6868a3fde4",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "ref": "nixos-22.11",
+        "repo": "nixpkgs",
+        "type": "github"
       }
     },
     "root": {
       "inputs": {
+        "bp": "bp",
         "nixpkgs": "nixpkgs"
       }
     }

flake.nix

@@ -1,7 +1,14 @@
 {
   description = "Simple, functional, dependency free string manipulation in Vanilla JS";
 
-  outputs = { self, nixpkgs }: 
+  inputs = {
+    nixpkgs.url = "github:NixOS/nixpkgs/nixos-22.11";
+    # bp.url = "github:serokell/nix-npm-buildpackage";
+    bp.url = "github:sbrow/nix-npm-buildpackage";
+    bp.inputs.nixpkgs.follows = "nixpkgs";
+  };
+
+  outputs = { bp, self, nixpkgs }: 
   let
     pkgs = nixpkgs.legacyPackages.x86_64-linux;
   in {
@@ -11,23 +18,9 @@
       ];
     };
 
-    checks.x86_64-linux.default = pkgs.stdenv.mkDerivation {
-        name = "strings-check";
+    checks.x86_64-linux.default = bp.outputs.legacyPackages.x86_64-linux.buildYarnPackage {
         src = ./.;
-
-        nativeBuildInputs = with pkgs; [ yarn ];
-        buildPhase = ''
-          # this line removes a bug where value of $HOME is set to a non-writable /homeless-shelter dir
-          export HOME=$(pwd)
-
-          yarn
-          yarn test
-        '';
-        checkPhase = ''
-          yarn test
-        '';
-        installPhase = ''
-        '';
+        yarnBuildMore = "yarn test";
     };
   };
 }

src/index.spec.ts

@@ -5,6 +5,21 @@ import {
 } from './index';
 
 describe('strings', () => {
+    describe('startsWith', () => {
+        it('returns true if haystack starts with needle', () => {
+            expect(startsWith('foo', 'foobar')).toBe(true);
+        })
+        it('returns true when haystack is needle', () => {
+            expect(startsWith('foo', 'foo')).toBe(true);
+        })
+        it('works', () => {
+            fc.assert(fc.property(fc.string(), fc.string(), (needle, haystack) => {
+                if (haystack.indexOf(needle) == 0) {
+                    expect(startsWith(needle, haystack)).toBe(true);
+                }
+            }));
+        })
+    });
 //   describe('afterFirstWord', () => {
     // it('removes the first word', () => {
     //   fc.assert(fc.property(fc.string(), (str) => {