我的npm update命令出现以下错误:
> pngquant-bin@4.0.0 postinstall /var/www/pp/20180315202846/node_modules/pngquant-bin
> node lib/install.js
? The `/var/www/pp/20180315202846/node_modules/pngquant-bin/vendor/pngquant` binary doesn't seem to work correctly
? pngquant pre-build test failed
? compiling from source
? pngquant pre-build test passed successfully
? RequestError: pngquant failed to build, make sure that libpng-dev is installed
at ClientRequest.req.once.err (/var/www/pp/20180315202846/node_modules/pngquant-bin/node_modules/got/index.js:111:21)
at Object.onceWrapper (events.js:272:13)
at ClientRequest.emit (events.js:180:13)
at ClientRequest.onConnect (/var/www/pp/20180315202846/node_modules/pngquant-bin/node_modules/tunnel-agent/index.js:168:23)
at Object.onceWrapper (events.js:272:13)
at ClientRequest.emit (events.js:180:13)
at Socket.socketOnData (_http_client.js:476:11)
at Socket.emit (events.js:180:13)
at addChunk (_stream_readable.js:269:12)
at readableAddChunk (_stream_readable.js:256:11)
npm WARN optional …