adding ability to use package.json version in comparison

README.md

@@ -65,6 +65,7 @@ Options
   -d, --dev-only        Look at devDependencies only (skip dependencies).
   -i, --ignore          Ignore dependencies based on succeeding glob.
   -E, --save-exact      Save exact version (x.y.z) instead of caret (^x.y.z) in package.json.
+  -P, --package-version Use the version in package.json for comparison instead of node_modules
   --specials            List of depcheck specials to include in check for unused dependencies.
   --no-color            Force or disable color output.
   --no-emoji            Remove emoji support. No emoji in default in CI environments.
@@ -150,6 +151,12 @@ Install packages using `--save-exact`, meaning exact versions will be saved in p
 
 Applies to both `dependencies` and `devDependencies`.
 
+#### `-P, --package-version`
+
+Compare versions using the package.json defined version instead of what version of the package is installed in node_modules.
+
+This allows you to update the package.json file to the latest version even if the latest version is installed in node_modules (because your package.json range covers the latest version).
+
 #### `--specials`
 
 Check special (e.g. config) files when looking for unused dependencies.

lib/cli.js

@@ -33,6 +33,7 @@ const cli = meow({
           -d, --dev-only        Look at devDependencies only (skip dependencies).
           -i, --ignore          Ignore dependencies based on succeeding glob.
           -E, --save-exact      Save exact version (x.y.z) instead of caret (^x.y.z) in package.json.
+          -P, --package-version Use the version in package.json for comparison instead of node_modules
           --specials            List of depcheck specials to include in check for unused dependencies.
           --no-color            Force or disable color output.
           --no-emoji            Remove emoji support. No emoji in default in CI environments.
@@ -52,7 +53,8 @@ const cli = meow({
             p: 'production',
             d: 'dev-only',
             E: 'save-exact',
-            i: 'ignore'
+            i: 'ignore',
+            P: 'package-version'
         },
         default: {
             dir: pkgDir.sync() || process.cwd(),
@@ -69,7 +71,8 @@ const cli = meow({
             'save-exact',
             'color',
             'emoji',
-            'spinner'
+            'spinner',
+            'package-version'
         ],
         string: [
             'ignore',
@@ -91,7 +94,8 @@ const options = {
     installer: process.env.NPM_CHECK_INSTALLER || 'auto',
     debug: cli.flags.debug,
     spinner: cli.flags.spinner,
-    ignore: cli.flags.ignore
+    ignore: cli.flags.ignore,
+    packageVersion: cli.flags.packageVersion
 };
 
 if (options.debug) {

lib/in/create-package-summary.js

@@ -62,7 +62,19 @@ function createPackageSummary(moduleName, currentState) {
 
             const versionWanted = semver.maxSatisfying(versions, packageJsonVersion);
 
-            const versionToUse = installedVersion || versionWanted;
+            let  versionToUse = installedVersion || versionWanted;
+
+            if (currentState.get('packageVersion')) {
+              if(!packageJsonVersion) {
+                throw new Error(`
+Trying to update with --package-version enabled but ${moduleName} doesn't exist in your package.json.
+
+Consider using --skip-unused to solve this issue
+`);
+              }
+              versionToUse = packageJsonVersion.replace(/^[^~]/, '');
+            }
+
             const usingNonSemver = semver.valid(latest) && semver.lt(latest, '1.0.0-pre');
 
             const bump = semver.valid(latest) &&

lib/state/state.js

@@ -20,6 +20,7 @@ const defaultOptions = {
     spinner: false,
     installer: 'npm',
     ignore: [],
+    packageVersion: false,
 
     globalPackages: {},
     cwdPackageJson: {devDependencies: {}, dependencies: {}},