simplify-dag:给定一个有向无环图，收缩直线运行到单个顶点

简化-dag 给定一个有向无环图，将直线简化为单个顶点。 const simplify = require ( 'simplify-dag' ) const digraph = require ( 'digraph-tag' ) let graph = digraph ` A -> B B -> C C -> D X -> Y Y -> Z Z -> D D -> U U -> V ` let simplified = simplify ( graph ) /* A X ↓ ↓ B Y ↓ ↓ [A, B, C] [X, Y, Z] C Z \___ ___/ \ / \ / Y --->