Answers for "upgrade all packages in package.json to latest"

update all packages in package.json

//To install major updates globally
npm install -g npm-check-updates

//To see a list of outdated packages
npm outdated

//To update the packages to their latest versions in package.json
ncu -u

//To install the new updates
npm update 	or 	npm install

update all dependencies npm package.json

npm i -g npm-check-updates
ncu -u
npm install

how to update my package.json

npm install -g npm-check-updates
/after install run following:
ncu -u

//Then this:
npm update

How to update all npm packages in package.json

npm i -g npm-check-updates
ncu -u
npm install