High memory usage for very big directories

[mrmlnc]

Environment

• OS Version: Windows 10 (1903)
• Node.js Version: 12.4.0

Actual behavior

FATAL ERROR: Ineffective mark-compacts near heap limit Allocation failed - JavaScript heap out of memory

Expected behavior

I see entries.

Steps to reproduce

1. Find directory with 2-4kk entries.
2. Run fast-glob with ** pattern

[mrmlnc]

Initial analysis:

• The _transform method call replace method for each entry. Memory profiling: 786MB
• The setBasePathForEntryPath method call startsWith method for each entry. Memory profiling: 180MB

Steps:

• Verify that memory consumption is reduced without calling these methods.

• Verify that CPU consumption is reduced without calling these methods.

[mrmlnc]

Will be fixed with fast-glob@3.0.2.

4.1GB (37s) → 0.8GB (25s)