Key Collision Handling

When key replacements or transformations cause multiple keys to map to the same output key, collision handling determines what happens.

Enabling Collision Handling

#![allow(unused)]
fn main() {
let result = JSONTools::new()
    .flatten()
    .key_replacement("regex:(User|Admin)_", "")
    .handle_key_collision(true)
    .execute(json)?;
}

result = (jt.JSONTools()
    .flatten()
    .key_replacement("regex:(User|Admin)_", "")
    .handle_key_collision(True)
    .execute(data)
)

How It Works

With .handle_key_collision(true), when two keys collide after transformation, their values are collected into an array:

// Input
{"User_name": "John", "Admin_name": "Jane"}

// With key_replacement("regex:(User|Admin)_", "") + handle_key_collision(true)
// Output
{"name": ["John", "Jane"]}

Without collision handling, the last value wins (overwrites previous values).

Collision with Filtering

Collision handling respects filters. If a colliding value would be filtered out (e.g., empty string with .remove_empty_strings(true)), it is excluded from the collected array:

// Input
{"User_name": "John", "Admin_name": "", "Guest_name": "Bob"}

// With remove_empty_strings(true) + handle_key_collision(true)
// Output
{"name": ["John", "Bob"], "guest_name": "Bob"}

Works with Both Modes

Collision handling works during both .flatten() and .unflatten() operations.