How to Validate FormArray length in angular2

Question

I have a data driven form in angular2 like below

this.formBuilder.group({
  \'name\': [\'\',Validators.required],
  \'description\': [\'\', Validators.required],         


        

Answer 1

Validators.required does the magic for you:

// using required 

this.formGroup = this.formBuilder.group({
    taskTreeId: [Common.UID()],
    executionProgrammedTime: ["", [Validators.required]],
    description: [""],
    tasks: this.formBuilder.array([], Validators.required)
});  

// using custom validation

export const minLengthArray = (min: number) => {
  return (c: AbstractControl): {[key: string]: any} => {
    if (c.value.length >= min)
      return null;

    return { MinLengthArray: true};
  }
}

 this.formGroup = this.formBuilder.group({
        taskTreeId: [Common.UID()],
        executionProgrammedTime: ["", [Validators.required]],
        description: [""],
        tasks: this.formBuilder.array([], minLengthArray(2))
    });

SAVE