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npm-install-g-ios-deploy doesn't work on Mojave
I was having this problem but it is closed so I can’t update there. In xcode 11.0 you will likely need to go to xcode/preferences/locations/command line tools choice and click the drop down so that Xcode 11.0 shows up. It’s not selected by default and it looks like npm will fail to install ios-deploy regardless of what parameters you use unless you manually select command line tools. At least one other tool showed xcode as “not installed” until command line tools were manually selected even though trying to run xcode-select recognizes command line tools are installed.