Implement fetching, filtering and tests

src/filter.ts

@@ -0,0 +1,38 @@
+import * as jsyaml from 'js-yaml'
+import * as minimatch from 'minimatch'
+
+export default class Filter {
+  rules: {[key: string]: minimatch.IMinimatch[]} = {}
+
+  constructor(yaml: string) {
+    const doc = jsyaml.safeLoad(yaml)
+    if (typeof doc !== 'object') {
+      this.throwInvalidFormatError()
+    }
+
+    for (const name of Object.keys(doc)) {
+      const patterns = doc[name] as string[]
+      if (!Array.isArray(patterns)) {
+        this.throwInvalidFormatError()
+      }
+      if (!patterns.every(x => typeof x === 'string')) {
+        this.throwInvalidFormatError()
+      }
+      this.rules[name] = patterns.map(x => new minimatch.Minimatch(x))
+    }
+  }
+
+  // Returns dictionary with match result per rules group
+  match(paths: string[]): {[key: string]: boolean} {
+    const result: {[key: string]: boolean} = {}
+    for (const [key, patterns] of Object.entries(this.rules)) {
+      const match = paths.some(fileName => patterns.some(rule => rule.match(fileName)))
+      result[key] = match
+    }
+    return result
+  }
+
+  private throwInvalidFormatError(): never {
+    throw new Error('Invalid filter YAML format: Expected dictionary of string arrays')
+  }
+}