Remove 'findup' dependency (palantir#2681)

package.json

@@ -39,7 +39,6 @@
     "babel-code-frame": "^6.22.0",
     "colors": "^1.1.2",
     "diff": "^3.2.0",
-    "findup-sync": "~0.3.0",
     "glob": "^7.1.1",
     "optimist": "~0.6.0",
     "resolve": "^1.3.2",
@@ -55,7 +54,6 @@
     "@types/chai": "^3.5.0",
     "@types/colors": "^1.1.3",
     "@types/diff": "0.0.31",
-    "@types/findup-sync": "^0.3.29",
     "@types/glob": "^5.0.30",
     "@types/js-yaml": "^3.5.29",
     "@types/mocha": "^2.2.35",

src/configuration.ts

@@ -15,7 +15,6 @@
  * limitations under the License.
  */
 
-import findup = require("findup-sync");
 import * as fs from "fs";
 import * as path from "path";
 import * as resolve from "resolve";
@@ -122,8 +121,8 @@ export function findConfigurationPath(suppliedConfigFilePath: string | null, inp
         }
     } else {
         // search for tslint.json from input file location
-        let configFilePath = findup(CONFIG_FILENAME, { cwd: inputFilePath, nocase: true });
-        if (configFilePath != null && fs.existsSync(configFilePath)) {
+        let configFilePath = findup(CONFIG_FILENAME, inputFilePath);
+        if (configFilePath !== undefined) {
             return path.resolve(configFilePath);
         }
 
@@ -141,6 +140,35 @@ export function findConfigurationPath(suppliedConfigFilePath: string | null, inp
     }
 }
 
+/**
+ * Find a file by name in a directory or any ancestory directory.
+ * This is case-insensitive, so it can find 'TsLiNt.JsOn' when searching for 'tslint.json'.
+ */
+function findup(filename: string, directory: string): string | undefined {
+    while (true) {
+        const res = findFile(directory);
+        if (res) {
+            return res;
+        }
+
+        const parent = path.dirname(directory);
+        if (parent === directory) {
+            return undefined;
+        }
+        directory = parent;
+    }
+
+    function findFile(cwd: string): string | undefined {
+        if (fs.existsSync(path.join(cwd, filename))) {
+            return filename;
+        }
+
+        // Try reading in the entire directory and looking for a file with different casing.
+        const filenameLower = filename.toLowerCase();
+        return fs.readdirSync(cwd).find((entry) => entry.toLowerCase() === filenameLower);
+    }
+}
+
 /**
  * Used Node semantics to load a configuration file given configFilePath.
  * For example: