WKWebView equivalent for UIWebView's scalesPageToFit

I am updating my iOS app to replace UIWebView with WKWebView. However I don't understand how to achieve the same behavior with WKWebView. With UIWebView I used scalesPageToFit to ensure the web pag was displayed with the same size as the screen size (so as to appear full screen without scrolling).

I found that solution on the web however it does not work :

- (void)webView:(WKWebView *)webView didCommitNavigation:(WKNavigation *)navigation {
    NSString *javascript = @"var meta = document.createElement('meta');meta.setAttribute('name', 'viewport');meta.setAttribute('content', 'width=device-width, initial-scale=1.0, maximum-scale=1.0, user-scalable=no');document.getElementsByTagName('head')[0].appendChild(meta);";
    [webView evaluateJavaScript:javascript completionHandler:nil];
}

you can also try the WKUserScript.

here's my working config:

NSString *jScript = @"var meta = document.createElement('meta'); meta.setAttribute('name', 'viewport'); meta.setAttribute('content', 'width=device-width'); document.getElementsByTagName('head')[0].appendChild(meta);";

WKUserScript *wkUScript = [[WKUserScript alloc] initWithSource:jScript injectionTime:WKUserScriptInjectionTimeAtDocumentEnd forMainFrameOnly:YES];
WKUserContentController *wkUController = [[WKUserContentController alloc] init];
[wkUController addUserScript:wkUScript];

WKWebViewConfiguration *wkWebConfig = [[WKWebViewConfiguration alloc] init];
wkWebConfig.userContentController = wkUController;

wkWebV = [[WKWebView alloc] initWithFrame:self.view.frame configuration:wkWebConfig];

you can add additional configuration to your WKWebViewConfiguration.

Echo of nferocious76's answer, in swift code: Swift2.x version

let jscript = "var meta = document.createElement('meta'); meta.setAttribute('name', 'viewport'); meta.setAttribute('content', 'width=device-width'); document.getElementsByTagName('head')[0].appendChild(meta);"
let userScript = WKUserScript(source: jscript, injectionTime: WKUserScriptInjectionTime.AtDocumentEnd, forMainFrameOnly: true)
let wkUController = WKUserContentController()
wkUController.addUserScript(userScript)
let wkWebConfig = WKWebViewConfiguration()
wkWebConfig.userContentController = wkUController
let youWebView = WKWebView(frame: CGRectZero, configuration: wkWebConfig)

swift3 version

let jscript = "var meta = document.createElement('meta'); meta.setAttribute('name', 'viewport'); meta.setAttribute('content', 'width=device-width'); document.getElementsByTagName('head')[0].appendChild(meta);"
let userScript = WKUserScript(source: jscript, injectionTime: .atDocumentEnd, forMainFrameOnly: true)
let wkUController = WKUserContentController()
wkUController.addUserScript(userScript)
let wkWebConfig = WKWebViewConfiguration()
wkWebConfig.userContentController = wkUController
let yourWebView = WKWebView(frame: self.view.bounds, configuration: wkWebConfig)

Similar to @nferocious76's but in Swift language

var scriptContent = "var meta = document.createElement('meta');"
scriptContent += "meta.name='viewport';"
scriptContent += "meta.content='width=device-width';"
scriptContent += "document.getElementsByTagName('head')[0].appendChild(meta);"

webView.evaluateJavaScript(scriptContent, completionHandler: nil)

I figured out below soultion. For making the content to fit with the device size.

func webView(_ webView: WKWebView, didCommit navigation: WKNavigation!) {     for making the content to fit with the device size
    let jscript = "var meta = document.createElement('meta'); meta.setAttribute('name', 'viewport'); meta.setAttribute('content', 'width=device-width'); document.getElementsByTagName('head')[0].appendChild(meta);"
    webView.evaluateJavaScript(jscript)
}