JavaScript Feature Reference: findIndex() Method Web Browser Support Test

Last reviewed/updated: 09 Feb 2018 | Published: 09 Feb 2018 | Status: Active
Web browser support: Internet Explorer 10+, Edge 12+, Firefox 6+, Chrome 30+, Opera 17+

1. Introduction

In this web page there are two web browser JavaScript feature support tests; 1.) a feature implementation test, and 2.) a feature capability test. First, the implementation test is run. The implementation test determines if the web browser recognizes the JavaScript findIndex() method. The implementation test is a simple test for the presence of web browser support, and a definitive test for the absence of web browser support. If the web browser does not recognize the JavaScript findIndex() method, the testing is stopped and the implementation test reports: Fail (no support): The web browser does not recognize the JavaScript findIndex() method. The web browser does not support the JavaScript findIndex() method.

If the web browser recognizes the JavaScript findIndex() method, the capability test is run. The capability test determines if the web browser's implementation of the JavaScript findIndex() method includes support for at least one findIndex() method capability. The capability test is a more definitive, albeit not an all inclusive, test for the presence of web browser support. If the web browser's implementation of the JavaScript findIndex() method includes support for the tested capability, the capability test reports: Pass (at least partial/possibly full support): The web browser recognizes the JavaScript findIndex() method, and supports at least one findIndex() method capability. The web browser at least partially/possibly fully supports the JavaScript findIndex() method. Positive determination of full web browser support is beyond the scope of this test. If the web browser's implementation of the JavaScript findIndex() method does not include support for the tested capability, the capability test reports: Pass/Fail (partial support): The web browser recognizes the JavaScript findIndex() method, but does not support at least one findIndex() method capability. The web browser partially supports the JavaScript findIndex() method.

The web browser support test source code is shown in Section 2.1. The web browser support test source code is run in Section 2.2, which shows the web browser support test result.

1.1. findIndex() Method Web Browser Support

  • Pass (at least partial/possibly full support): ED12+, FF25+, CH45+, OP32+.
  • Fail (no support): IE11-, SF5.1.7-.

1.2. Abbreviations

  • IE = Internet Explorer.
  • ED = Edge = EdgeHTML rendering engine (ED12+) and/or Edge browser (ED20+).
  • FF = Firefox.
  • SF = Safari.
  • CH = Chrome.
  • OP = Opera.

2. findIndex() Method Web Browser Support Test

2.1. Web Browser Support Test Source Code

<script>
var arrayLiteral = [10, 20, 30, 40];
if (arrayLiteral.findIndex){
 var element = document.getElementById("testId");
 var arrayElement,
  elementIndex,
  arr;
 var objectLiteral = {propertyOne: 5};
 var callbackFunction = function(element, index, array){ // Callback function passed three arguments; 1.) array element value (required), 2.) array element numeric index (optional), and 3.) array that findIndex() method was called on (optional). The element, index, and array parameters are author-defined local variables; meaning, can use any valid identifier (eg, elementFoo, indexFoo, arrayFoo).
  arrayElement = element; // Set callback function arguments on outer scoped variables for use in if conditional below.
  elementIndex = index;
  arr = array;
  return (element + this.propertyOne) === 35; // Return statement can be any boolean expression; but, typically includes array element value. When callback function returns boolean true, findIndex() method returns array element numeric index. Otherwise, continue iterating over array elements. If no boolean expression evaluates to true, findIndex() method returns -1.
 }
 var findIndexReturnValue = arrayLiteral.findIndex(callbackFunction, objectLiteral); // Call findIndex() method and set findIndex() method return value on variable. Callback function this value is objectLiteral.
 if ((findIndexReturnValue === 2) && (arrayElement === 30) && (elementIndex === 2) && (arr === arrayLiteral)){
  document.write("<p><b>Pass</b> (at least partial/possibly full support): The web browser recognizes the JavaScript <code>findIndex()</code> method, and supports at least one <code>findIndex()</code> method capability. The web browser at least partially/possibly fully supports the JavaScript <code>findIndex()</code> method. Positive determination of full web browser support is beyond the scope of this test.</p>");
 } else {
  document.write("<p><b>Pass/Fail</b> (partial support): The web browser recognizes the JavaScript <code>findIndex()</code> method, but does not support at least one <code>findIndex()</code> method capability. The web browser partially supports the JavaScript <code>findIndex()</code> method.</p>");
 }
} else {
 document.write("<p><b>Fail</b> (no support): The web browser does not recognize the JavaScript <code>findIndex()</code> method. The web browser does not support the JavaScript <code>findIndex()</code> method.</p>");
}
</script>

2.2. Web Browser Support Test Result


3. Resources And Additional Information