feat: support version prefixes for dependencies

README.md

@@ -72,7 +72,7 @@ Simply place those dependencies inside the `basePackageValues` object which repr
 new `package.json` to be created.
 
 Keep the version number string empty (`""`) to have the plugin resolve the version. To use a version which is
-different, set the version string deliberately here.
+different, set the version string deliberately here. You can also use version prefixes `"^"` or `"~"` which will resolve the installed version and prepend the prefix.
 
 ```
 const basePackageValues = {
@@ -88,16 +88,19 @@ const basePackageValues = {
   devDependencies: {
     "cross-var": "^1.1.0",
     "cross-env": "",
+    "lodash": "^",
   },
   peerDependencies: {
-    "react" : "",
+    "react" : "~",
   }
 }
 ```
 
-In this example, `cross-var` has deliberately been set to version `^1.1.0`, and regardless of what is actually installed
-it will use this version.
-`cross-env` however will pull its version number from `node_modules`.
+In this example:
+- `cross-var` has been set to version `^1.1.0` explicitly and will use this exact version
+- `cross-env` will pull its version number from `node_modules` (e.g., `8.0.1`)
+- `lodash` will resolve the installed version with a caret prefix (e.g., `^4.17.21`)
+- `react` will resolve the installed version with a tilde prefix (e.g., `~18.2.0`)
 
 This is mostly useful for adding dependencies which are required at runtime but which are not picked up in your webpack
 bundle. Such as `cross-var` in this example which injects environment variables into a run script in a cross-platform

index.js

@@ -77,6 +77,11 @@ function logIfDebug(something, object = "") {
   }
 }
 
+function isVersionPrefix(versionString) {
+  // Check if the string is a version prefix like "^" or "~"
+  return /^(\^|~)$/.test(versionString);
+}
+
 const nodeModulesPart = "node_modules";
 
 function getNameFromPortableId(raw) {
@@ -306,11 +311,38 @@ GeneratePackageJsonPlugin.prototype.apply = function (compiler) {
         for (let k = 0; k < nonWebpackModuleNames.length; k += 1) {
           const moduleName = nonWebpackModuleNames[k];
           let useVersionMap = !this.useInstalledVersions;
-
-          if (basePackageValues[dependencyType] && basePackageValues[dependencyType][moduleName] && basePackageValues[dependencyType][moduleName].length > 0) {
-            logIfDebug(`GPJWP: Adding deliberate module in "${dependencyType}" with version set deliberately: ${moduleName} -> ${basePackageValues[dependencyType][moduleName]}`);
-            if (dependencyType === "dependencies") {
-              modules[moduleName] = basePackageValues[dependencyType][moduleName];
+          const versionString = basePackageValues[dependencyType] && basePackageValues[dependencyType][moduleName];
+          const isPrefix = isVersionPrefix(versionString);
+
+          if (versionString && versionString.length > 0) {
+            if (isPrefix && this.useInstalledVersions) {
+              // If it's a version prefix, resolve the installed version and apply the prefix
+              logIfDebug(`GPJWP: Adding module in "${dependencyType}" with version prefix: ${moduleName} -> ${versionString}<installed-version>`);
+              const installedVersion = getInstalledVersionForModuleName(moduleName);
+              if (installedVersion != null) {
+                // "versionString" is only the prefix (e.g. "^") as checked by isPrefix() earlier
+                // - so we take the installed version and add the prefix to it for the final version string
+                const prefixedVersion = versionString + installedVersion;
+
+                if (dependencyType === "dependencies") {
+                  modules[moduleName] = prefixedVersion;
+                } else {
+                  if (!basePackageValues[dependencyType]) {
+                    basePackageValues[dependencyType] = {};
+                  }
+                  basePackageValues[dependencyType][moduleName] = prefixedVersion;
+                  delete modules[moduleName];
+                }
+              } else {
+                console.warn(`${pluginPrefix}Couldn't find installed version for module "${moduleName}" with prefix "${versionString}"`);
+                useVersionMap = true;
+              }
+            } else {
+              // Use the version string as-is (it's an explicit version or prefix but useInstalledVersions is false)
+              logIfDebug(`GPJWP: Adding deliberate module in "${dependencyType}" with version set deliberately: ${moduleName} -> ${versionString}`);
+              if (dependencyType === "dependencies") {
+                modules[moduleName] = versionString;
+              }
             }
           } else if (this.useInstalledVersions) {
             const version = getInstalledVersionForModuleName(moduleName);