Question 1

How to filter JSON data by regex using ajson?

Accepted Answer

Use the `=~` operator in JSONPath expressions, e.g., `$.[?(@.mail =~ '.+@example\.com')]` to match strings against regular expressions. The script engine supports this directly, as shown in the regex operator example.

Question 2

ajson vs standard Go encoding/json: which is better for my project?

Accepted Answer

Use ajson for dynamic querying with JSONPath when the JSON structure is unknown or changes frequently; use encoding/json for static schemas where type safety and performance are prioritized. ajson adds flexibility but with higher memory usage.

Question 3

Can ajson handle large JSON files or streams efficiently?

Accepted Answer

While it supports streaming via the CLI's STDIN input, benchmarks indicate increased memory allocations, so for very large datasets, performance might degrade compared to optimized parsers. Consider chunking or alternative tools for massive files.

Question 4

How to add a custom function like median calculation to ajson?

Accepted Answer

Use the AddFunction method to define new functions, similar to the trim example in the README. This allows extending the script engine with domain-specific logic, though it requires additional Go code for implementation.

Question 5

Is ajson thread-safe for concurrent reads and writes?

Accepted Answer

Yes, node values are stored in atomic.Value, making concurrent access safe for read operations. However, manipulation like SetNumeric should be synchronized if multiple goroutines modify the same node to avoid race conditions.

Question 6

How to use the ajson CLI tool to process logs in real-time?

Accepted Answer

Pipe logs via STDIN with flags like -q for quiet mode, e.g., `docker logs -f | ajson -qm 'root($[?(@=="ERROR")])'`. The tool supports multiline JSON and filtering, as demonstrated in the console application examples.

ajson

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