Ask HN: Why does Node.js start so slow? | Hacker News Reader

Ask HN: Why does Node.js start so slow?

2 pointsFreeHugs6 comments

time php -r 'echo 123;'

outputs:

    123
    real 0m0.031s
    user 0m0.023s
    sys 0m0.008s

time python3 -c 'print (123)'

outputs:

    123
    
    real 0m0.022s
    user 0m0.019s
    sys 0m0.004s

time node -e 'console.log(123);'

outputs:

    123

    real 0m0.578s
    user 0m0.551s
    sys 0m0.028s

Why is the node version more than 10 times slower than the PHP and Python versions?

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What's your output for: `which node` and `node -v`

On my M1 Pro:

    python3 -c 'print (123)'    0.02s user 0.01s system 86% cpu 0.036 total
    node -e 'console.log(123)'  0.04s user 0.01s system 88% cpu 0.053 total

which node: /usr/bin/node

node -v: v10.24.0

And for you?

When I install it from https://deb.nodesource.com/setup_16.x then I get:

node -v: v16.15.0

And indeed, then the time goes down by a factor of 10:

time node -e 'console.log(123);'

Now outputs:

    123
    
    real 0m0.058s
    user 0m0.046s
    sys 0m0.013s

You're measuring how slowly your computer follows symlinks

Can you elaborate?

Take your original setup. Run it. Time it.

Now, using `which`, invoke it directly, instead of through the symlink. Time it again.

I guess the reason is that the runtime of node is so much larger than that of Python and PHP. I think the Node runtime is already at > 50MB as a binary.

I don't know how large Python and PHP runtimes are, but I know python is often stripped down to a few kilobytes for embedded systems.

I guess if you preload the runtimes before executing these commands, the execution should be fairly similar for each one (near zero, more depending on I/O).

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