Array Methods and Object Manipulation Questions

Focuses on language level array operations and common data transformation patterns together with manipulating objects or records. Includes array methods such as map, filter, reduce, sort, find and for each and when to use each method, stable and unstable sorting considerations, and performance implications of chained operations. Also covers object property manipulation, mapping between arrays and objects, merging and immutability patterns, and common transformation tasks in data processing pipelines. Candidates should understand algorithmic complexity of these operations, side effects versus pure functions, and practical usage in coding interviews and production code.