Coding-Medium-Circular-Buffer

The model receives the prompt (and optional system message). The run uses scorer javascript_function_tests with the JSON configuration below. Pass/fail and partial credit are determined entirely by that scorer against the model output; no human grading.

Return JSON only with a string field named code. The code must be dependency-free JavaScript, define the requested function in the top level or module.exports, and include no markdown, imports, require, timers, network, filesystem, eval, or placeholders.

Implement function createCircularBuffer(capacity, script). The script is a comma-separated string of operations: 'push:VALUE' adds a value to the buffer (dropping the oldest if full), 'pop' removes and returns the oldest value (or null if empty). Return an array of results: null for each push operation, and the popped value (or null if empty) for each pop operation.

Your JSON must look like {"code":"function createCircularBuffer(...) { ... }"}.

{
  "function_name": "createCircularBuffer",
  "timeout_ms": 100,
  "test_pass_threshold": 1,
  "partial_credit_threshold": 0.5,
  "tests": "[hidden executable tests]"
}