Function catchError

Catches all iteration errors up the chain (see Error Handling).

Below is explicit error handling, by injecting catchError into the pipeline:

import {pipe, catchError, map} from 'iter-ops';

const i = pipe(
    [1, 2, 3],
    map(a => {
        if (a % 2 === 0) {
            throw new Error('even number');
        }
        return a;
    }),
    catchError((err, ctx) => {
        console.log(err);
    })
);
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What you can do inside the error handler:

• nothing (we let it skip the value)
• provide a new/alternative value (via ctx.emit(value))
• re-throw the original error
• throw a new error

Below is implicit error handling, via catch, which just appends catchError to the pipeline:

import {pipe, map} from 'iter-ops';

const i = pipe(
    [1, 2, 3],
    map(a => {
        if (a % 2 === 0) {
            throw new Error('even number');
        }
        return a;
    })
)
    .catch((err, ctx) => {
        console.log(err);
    });
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See

• Error Handling
• catchError