feat(only): add it.only(10) syntax

README.md

@@ -61,6 +61,10 @@ output:
   10 passing (10ms)
 ```
 
+## Features
+
+* Supports `it.only(n)(...)` syntax to run single text N times
+
 ## Related projects
 
 * [focha](https://github.com/bahmutov/focha) - Mocha wrapper

src/index.js

@@ -1,15 +1,49 @@
 'use strict'
 
 const oldIt = global.it
-console.assert(typeof oldIt === 'function', 'missing global it function')
+
+function isFunction (x) {
+  return typeof x === 'function'
+}
+
+function isNumber (x) {
+  return typeof x === 'number'
+}
+
+function isNonNegative (x) {
+  return isNumber(x) && x >= 0
+}
+
+console.assert(isFunction(oldIt), 'missing global it function')
+console.assert(isFunction(oldIt.only), 'missing it.only function')
+
+function checkTimes (times) {
+  console.assert(isNonNegative(times), 'repeat times should be non-negative')
+}
+
+function only (times) {
+  if (!isNumber(times)) {
+    // probably plain it('name', ...) call
+    return oldIt.only.apply(null, arguments)
+  }
+
+  checkTimes(times)
+
+  return function (title, fn) {
+    let k
+    for (k = 0; k < times; k += 1) {
+      oldIt.only(k + 1 + ' ' + title, fn)
+    }
+  }
+}
 
 function repeatIt (times) {
-  if (typeof times !== 'number') {
+  if (!isNumber(times)) {
     // probably plain it('name', ...) call
     return oldIt.apply(null, arguments)
   }
 
-  console.assert(times >= 0, 'repeat times should be non-negative')
+  checkTimes(times)
 
   return function (title, fn) {
     let k
@@ -19,4 +53,6 @@ function repeatIt (times) {
   }
 }
 
+repeatIt.only = only
+
 module.exports = repeatIt

src/repeat-it-spec.js

@@ -10,6 +10,10 @@ describe('repeat-it', () => {
     counter += 1
   })
 
+  it('has .only function', () => {
+    console.assert(typeof it.only === 'function')
+  })
+
   after(() => {
     console.assert(counter === 10, 'runs ' + counter + ' times')
   })