Weighted Methods per Class

Overview

Weighted Methods per Class (WMC) is a class-level metric that captures overall class complexity by summing the complexity of every method. Classes with high WMC are harder to understand, test, and maintain. A very high WMC may indicate a God Class.

Formula

Each method's contribution equals its cyclomatic complexity (minimum 1). A class with three trivial methods and no branching has WMC = 3.

What tsmetrics includes in WMC

tsmetrics sums the CC of the following method kinds:

• Regular instance and static methods (method_definition)
• Constructors
• Getter and setter accessors
• Abstract method signatures (abstract_method_signature)

Arrow function class fields are not included as WMC contributors, because they are tracked as functions in the function table rather than as class methods.

Thresholds

thresholds:
  wmc:
    warning: 15
    error:   40

Interpretation

Example

class OrderProcessor {
  constructor() {}              // CC=1

  validate(order: Order) {     // CC=3 (2 ifs)
    if (!order.items.length) return false;
    if (!order.customer) return false;
    return true;
  }

  process(order: Order) {      // CC=4 (3 branches)
    if (!this.validate(order)) return;
    if (order.isPriority) { /* ... */ }
    else { /* ... */ }
  }
}
// WMC = 1 + 3 + 4 = 8

Usage in detection strategies

• God Class — WMC > 47 is one of three required conditions

JSON field

In JSON output, the field is named wmc on each class record.

References

• Chidamber, S. R. & Kemerer, C. F. (1994). A Metrics Suite for Object Oriented Design. IEEE Transactions on Software Engineering.