Expression Error handling for missing properties in large paginated datasets

Problem Context

When working with After Effects expressions that sample from large datasets or paginated collections, the expression engine evaluates each frame independently. This per-frame evaluation model creates challenges when expressions reference properties that may not exist in certain dataset states, particularly during pagination transitions.

Technical Constraints

• Expressions run in a sandboxed JavaScript environment with limited error recovery mechanisms
• The 'Expression Error' occurs when referencing non-existent properties, causing property reversion to defaults
• Large datasets require pagination to prevent render time degradation from inefficient loops
• Deeply nested expressions risk application hangs during preview

Core Challenge

Bounding a query to a specific dataset segment while maintaining stable expression evaluation across pagination boundaries presents an unresolved design question. The engine lacks built-in mechanisms to gracefully handle missing data references during dynamic dataset slicing.

Specific Questions

1. How can expressions safely query paginated data without triggering Expression Errors when dataset bounds change?
2. What patterns allow expressions to sample from time-offset datasets while preventing circular reference crashes?
3. Is there a documented approach for wrapping valueAtTime() calls to handle missing property references in large collections?