loading ./node_modules/.bin on the fly | only possible with zsh terminals, avoids setting traps to cd, etc...

.zshrc

# for loading node module bin files into PATH
NPM_LOCAL_MODULES=/dev/null

function npm_bin_loader() {
        CURRENT_NPM_MODULE=$NPM_LOCAL_MODULES

        if [ -d "node_modules" ]
        then
                NPM_LOCAL_MODULES="$(pwd)/node_modules/.bin"

        else
                NPM_LOCAL_MODULES=/dev/null
        fi

        if [ $NPM_LOCAL_MODULES != $CURRENT_NPM_MODULE ]
        then
                PATH=$(echo $PATH | sed -e 's|'$CURRENT_NPM_MODULE'|'$NPM_LOCAL_MODULES'|g')
        fi
        
        # just to check the path
        echo $PATH
}

# adding our helper to the change pwd hook
chpwd_functions+=("npm_bin_loader")

# export the path
export PATH=$NPM_LOCAL_MODULES:$PATH