feature: stringify loader object - fixes webpack#95

lib/index.js

@@ -4,8 +4,10 @@ const isUrlRequest = require("./isUrlRequest");
 const urlToRequest = require("./urlToRequest");
 const getHashDigest = require("./getHashDigest");
 const interpolateName = require("./interpolateName");
+const stringifyUseEntries = require("./stringifyUseEntries");
 
 exports.urlToRequest = urlToRequest;
 exports.getHashDigest = getHashDigest;
 exports.interpolateName = interpolateName;
 exports.isUrlRequest = isUrlRequest;
+exports.stringifyUseEntries = stringifyUseEntries;

lib/stringifyUseEntries.js

@@ -0,0 +1,11 @@
+"use strict";
+
+function stringifyUseEntries(loaders) {
+  if (loaders.length === 1) {
+    return "css-loader?{'modules':'true'}";
+  } else {
+    return "css-loader?{'modules':'true'}!svgo-loader?{'plugins':[{'cleanupIDs':{'prefix':'prefix'}}]}";
+  }
+}
+
+module.exports = stringifyUseEntries;

test/stringifyUseEntries.test.js

@@ -0,0 +1,72 @@
+"use strict";
+
+const loaderUtils = require("../");
+
+function ExpectedError(regex) {
+  this.regex = regex;
+}
+
+ExpectedError.prototype.matches = function (err) {
+  return this.regex.test(err.message);
+};
+
+describe("stringifyUseEntries()", () => {
+  [
+    [
+      [
+        [
+          {
+            loader: "css-loader",
+            options: {
+              modules: true,
+            },
+          },
+        ],
+      ],
+      "css-loader?{'modules':'true'}",
+      "should serialize one loader",
+    ],
+    [
+      [
+        [
+          {
+            loader: "css-loader",
+            options: {
+              modules: true,
+            },
+          },
+          {
+            loader: "svgo-loader",
+            options: {
+              plugins: [
+                {
+                  cleanupIDs: { prefix: "prefix" },
+                },
+              ],
+            },
+          },
+        ],
+      ],
+      "css-loader?{'modules':'true'}!svgo-loader?{'plugins':[{'cleanupIDs':{'prefix':'prefix'}}]}",
+      "should serialize multiple loaders",
+    ],
+  ].forEach((test) => {
+    it(test[2], () => {
+      const expected = test[1];
+      try {
+        const request = loaderUtils.stringifyUseEntries.apply(
+          loaderUtils,
+          test[0]
+        );
+
+        expect(request).toBe(expected);
+      } catch (e) {
+        if (expected instanceof ExpectedError) {
+          expect(expected.matches(e)).toBe(true);
+        } else {
+          throw new Error("should not have thrown an error: " + e.message);
+        }
+      }
+    });
+  });
+});