Month: 2026-04 — Frontend feature delivery and quality improvements for cBioPortal. The primary focus was enhancing mutation visualization and data reliability in cbioportal-frontend. Key features delivered: - Cancer Cell Fraction (CCF) and Clonality visualization added to the Plots tab as new options for plotting mutations, gated on per-gene ASCN data availability. This enables more accurate interpretation of ASCN-derived mutation annotations across genes with sufficient data. Major bugs fixed / robustness improvements: - Implemented gating logic to prevent stale or unsupported selections when ASCN data is absent; the UI now resets to a safe default to maintain valid plots. - Updated data-availability messaging to reflect samples without mutations or clonality as No mutation / Not profiled, reducing user confusion. - Data utility improvements to preserve valid zero values (using numeric checks) and to filter NA clonality values before deduplication, ensuring correct axis data and ordering. Overall impact and accomplishments: - Significantly improved visualization fidelity for ASCN-derived mutations, enabling researchers to compare CCF and clonality alongside cancer type with confidence. - Strengthened data handling and user guidance, reducing edge-case errors in the Plots tab. - Added comprehensive testing coverage and CI-visible validation artifacts to ensure long-term reliability. Technologies / skills demonstrated: - TypeScript, React, and frontend architecture adjustments in PlotsTab.tsx and PlotsTabUtils.tsx. - Advanced data processing with lodash (isNumber, uniq, and filtering) to preserve meaningful values. - Quality assurance through unit tests (PlotsTabUtils.spec.ts) and remote E2E screenshot testing with CI artifacts (MSK 50K, PIK3CA). Delivery detail: - Commit: 5cdceed5c529920dc2b66aae101b0ca5875508d4 (Add Cancer Cell Fraction and Clonality to Plots Tab, #5492).