Make --ignore relative

Author: blakeembrey

src/index.ts

@@ -252,13 +252,8 @@ export function create (options: CreateOptions = {}): Register {
     ...(options.ignoreDiagnostics || [])
   ].map(Number)
 
-  const ignore = options.skipIgnore ? [] : (
-    options.ignore || ['/node_modules/']
-  ).map(str => new RegExp(str))
-
   // Require the TypeScript compiler and configuration.
   const cwd = options.dir ? resolve(options.dir) : process.cwd()
-  const isScoped = options.scope ? (fileName: string) => relative(cwd, fileName).charAt(0) !== '.' : () => true
   const typeCheck = options.typeCheck === true || options.transpileOnly !== true
   const compiler = require.resolve(options.compiler || 'typescript', { paths: [cwd, __dirname] })
   const ts: typeof _ts = require(compiler)
@@ -269,6 +264,11 @@ export function create (options: CreateOptions = {}): Register {
   const configDiagnosticList = filterDiagnostics(config.errors, ignoreDiagnostics)
   const outputCache = new Map<string, string>()
 
+  const isScoped = options.scope ? (relname: string) => relname.charAt(0) !== '.' : () => true
+  const shouldIgnore = createIgnore(options.skipIgnore ? [] : (
+    options.ignore || ['/node_modules/']
+  ).map(str => new RegExp(str)))
+
   const diagnosticHost: _ts.FormatDiagnosticsHost = {
     getNewLine: () => ts.sys.newLine,
     getCurrentDirectory: () => cwd,
@@ -462,18 +462,24 @@ export function create (options: CreateOptions = {}): Register {
 
   let active = true
   const enabled = (enabled?: boolean) => enabled === undefined ? active : (active = !!enabled)
-  const ignored = (fileName: string) => !active || !isScoped(fileName) || shouldIgnore(fileName, ignore)
+  const ignored = (fileName: string) => {
+    if (!active) return true
+    const relname = relative(cwd, fileName)
+    return !isScoped(relname) || shouldIgnore(relname)
+  }
 
   return { ts, config, compile, getTypeInfo, ignored, enabled }
 }
 
 /**
  * Check if the filename should be ignored.
  */
-function shouldIgnore (filename: string, ignore: RegExp[]) {
-  const relname = normalizeSlashes(filename)
+function createIgnore (ignore: RegExp[]) {
+  return (relname: string) => {
+    const path = normalizeSlashes(relname)
 
-  return ignore.some(x => x.test(relname))
+    return ignore.some(x => x.test(path))
+  }
 }
 
 /**