EACCES permission errors can occur when packages are installed globally. If this is the case, npm may need to be set up to operate without elevated permissions.
Using sudo with npm is not recommended because it can lead to further complications.
This guide offers two options for resolving permission issues. Refer to the npm docs for full documentation and additional options.
The best way to avoid permission issues is to reinstall NodeJS and npm using a node version manager.
This guide will document nvm installation and usage. Refer to the nvm docs for full documentation. Refer to the npm docs for additional options and instructions for Windows.
New terminals will now use nvm. To verify, open a new terminal and run the following. If something prints, the installation was successful.
To download and install the latest LTS release of NodeJS, run:
Set the newly installed NodeJS as the default environment:
New terminals will now use the nvm-controlled NodeJS. To verify:
Global packages will now be installed in the ~/.nvm directory, so permission errors should no longer occur as long as npm is used without sudo.
Change the owner of npm's directories to the current user:
Since these global directories are no longer owned by root, packages can be installed globally without sudo.
To update an npm dependency, run the following, where <package-name> is the package to update:
For example, to update the @ionic/angular package to the release tagged latest, run:
It is recommended that packages get updated through the CLI since npm will now read package versions from the package-lock.json first.
There are a lot of code editors to choose from. Here are some of our favorites:
The debugger keyword can be used to debug an app. When most browsers encounters a debugger statement, running of JavaScript is stopped, and the browser will load its debugger. This can be used to set "breakpoints" in the app.
For example, if a function is not returning the correct value, the debugger can be used to step through the code and inspect variables.
When an app runs, it will pause at this function. From there, the developer tools can be used to run pieces of JavaScript, line by line, and inspect where exactly the function breaks.
By default, when an app is viewed in the browser, Ionic will apply the md mode. However, since Ionic components adapt according to their platform, it is helpful to be able to view what the app will look like on iOS. To do this, add ?ionic:mode=ios to the URL where the app is being served. For example, if the app is served on port 8100, the url would be: http://localhost:8100/?ionic:mode=ios.
This will not change which platform the browser detects. The platform is determined by device detection and inspecting the user-agent. To change the platform, the user-agent must be changed. To do this, open up Chrome DevTools with Ctrl+Shift+I(Cmd+Option+I on Mac), and then toggle device mode on with Ctrl+Shift+M(Cmd+Option+M on Mac).
Selecting devices from the device dropdown will change the user-agent, as well as the dimensions of the viewport.
The iOS simulator enables testing and debugging of an app before it reaches an actual device.
Before it can be used, Xcode, Apple's IDE, must be installed.
The Ionic CLI can then be used to run the app in the current directory on the simulator:
Passing in the -lc flag will enable livereload and log console output to a terminal.
Xcode can also be used to launch the emulator and debug an app.
Open up Xcode and open ../path-to-app/platforms/ios/myApp.xcodeproj.
After the app loads, console output and device logs will be printed inside of Xcode's output window.
While the Android SDK comes with a stock emulator, it can be slow and unresponsive at times.
Genymotion is an alternate emulator that is faster, and still allows access to native functionality like GPS and camera.