I'm trying to use node's spawn/exec functions from the child_process module. But I'm noticing a strange difference between what I see in a real terminal and on the command line. Here's an example:
Terminal:
$ redis-cli
127.0.0.1:6379> hmset hash name Jack age 33
OK
127.0.0.1:6379> hscan hash 0
1) "0"
2) 1) "name"
2) "Jack"
3) "age"
4) "33"
In node.js:
const child = exec("redis-cli");
child.stdin.setDefaultEncoding("utf-8");
child.stdout.on("data", data => console.log(data.toString()));
child.stdin.write("hmset hash name Jack age 33\n"); // same as first command from cli example
await new Promise(r => setTimeout(r, 1000));
child.stdin.write("hscan hash 0\n"); // same as second command from cli example
await new Promise(r => setTimeout(r, 1000));
This is what gets written to the console:
OK
0
name
Jack
age
33
In this case the numbers 1), 2) etc. are missing. Any ideas how I can persuade child_process to also write them to the console? I'm guessing that this particular example is a quirk of how redis-cli is implemented, but the data must be going somewhere.
the await new Promise(...) calls are just to ensure that the previous command is finished for this simple example.
As is often the case, I figured this out within one minute of posting the question.
redis-cli tries to detect if the standard output is a terminal. This problem is solved by using
const child = exec("redis-cli --no-raw");
instead of
const child = exec("redis-cli");
RTFM.