feat: only use the number of format placeholders in the title

README.md

@@ -9,3 +9,44 @@ Find the implementation in [src/index.js](./src/index.js)
 - [it-each-spec.js](./cypress/integration/it-each-spec.js) uses the `it.each` helper to generate multiple `it` tests given a data array
 - [describe-each-spec.js](./cypress/integration/describe-each-spec.js) uses `describe.each` helper to create `describe` blocks for each item in the given data array
 - [mocha-each-spec.js](cypress/integration/mocha-each-spec.js) uses 3rd party [mocha-each](https://github.com/ryym/mocha-each) to generate `it` tests for each data item
+
+## Small print
+
+Author: Gleb Bahmutov <[email protected]> © 2021
+
+- [@bahmutov](https://twitter.com/bahmutov)
+- [glebbahmutov.com](https://glebbahmutov.com)
+- [blog](https://glebbahmutov.com/blog)
+- [videos](https://www.youtube.com/glebbahmutov)
+- [presentations](https://slides.com/bahmutov)
+- [cypress.tips](https://cypress.tips)
+
+License: MIT - do anything with the code, but don't blame me if it does not work.
+
+Support: if you find any problems with this module, email / tweet /
+[open issue](https://github.com/bahmutov/cypress-each/issues) on Github
+
+## MIT License
+
+Copyright (c) 2021 Gleb Bahmutov <[email protected]>
+
+Permission is hereby granted, free of charge, to any person
+obtaining a copy of this software and associated documentation
+files (the "Software"), to deal in the Software without
+restriction, including without limitation the rights to use,
+copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the
+Software is furnished to do so, subject to the following
+conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
+OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
+HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+OTHER DEALINGS IN THE SOFTWARE.

cypress/expected.json

@@ -24,5 +24,9 @@
       "adds null and 10 then returns NaN": "passed",
       "adds {} and [] then returns NaN": "passed"
     }
+  },
+  "format": {
+    "I am a person": "passed",
+    "I am a person at 42": "passed"
   }
 }

cypress/integration/format-spec.js

@@ -0,0 +1,23 @@
+/// <reference types="cypress" />
+
+import '../..'
+
+describe('format', () => {
+  const person = {
+    name: 'Joe',
+  }
+
+  // it should only use the number of arguments
+  // in the string format, and not all available arguments
+  it.each([['person', person, 42]])('I am a %s', (name, who, life) => {
+    expect(name).to.equal('person')
+    expect(who).to.equal(person)
+    expect(life).to.equal(42)
+  })
+
+  it.each([['person', 42, person]])('I am a %s at %d', (name, life, who) => {
+    expect(name).to.equal('person')
+    expect(who).to.equal(person)
+    expect(life).to.equal(42)
+  })
+})

src/index.js

@@ -3,16 +3,23 @@
 // standard Node module "util" has "format" function
 const { format } = require('util')
 
+function formatTitle(pattern, ...values) {
+  // count how many format placeholders are in the pattern
+  // by counting the "%" characters
+  const count = pattern.match(/%/g).length
+  return format.apply(null, [pattern].concat(values.slice(0, count)))
+}
+
 if (!it.each) {
   it.each = (values) => {
     return function (titlePattern, testCallback) {
       values.forEach((value) => {
         // define a test for each value
         if (Array.isArray(value)) {
-          const title = format(titlePattern, ...value)
+          const title = formatTitle(titlePattern, ...value)
           it(title, testCallback.bind(null, ...value))
         } else {
-          const title = format(titlePattern, value)
+          const title = formatTitle(titlePattern, value)
           it(title, testCallback.bind(null, value))
         }
       })
@@ -26,10 +33,10 @@ if (!describe.each) {
       // define a test for each value
       values.forEach((value) => {
         if (Array.isArray(value)) {
-          const title = format(titlePattern, ...value)
+          const title = formatTitle(titlePattern, ...value)
           describe(title, testCallback.bind(null, ...value))
         } else {
-          const title = format(titlePattern, value)
+          const title = formatTitle(titlePattern, value)
           describe(title, testCallback.bind(null, value))
         }
       })