How to Solve @Vue/cli3.X Using less Error

To use less, you need to download less and less loader

npm install less less-loader --save-dev

In this way, an error will be reported after running. The reason is that the loader version is too high. Just reduce the version

Uninstall less loader
NPM uninstall less loader
install less loader
NPM install less- loader@7.x --save-dev

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