alternative switch not evaluating the value of switched variable

alternative-switch.js

lines.forEach((line, index) => {
      switch (true) {
        // the this.isACondition return true and will be evaluated o not otherwise won't be
        case this.isACondition(line):
          doSomething++;
          break;
        case this.isAnOtherCondition(line):
          doElseThing++;
          break;
        case this.somethingElseThatReturnTrueOrFalse(line, index):
          doAnotherthing++;
          break;
      }
    });