How to use the ngx-custom-validators.CustomValidators.base64 function in ngx-custom-validators

minLength: {
      func: Validators.minLength,
      params: ["minLength"]
    },
    pattern: {
      func: Validators.pattern,
      params: ["pattern"]
    },
    required: {
      func: Validators.required
    },
    requiredTrue: {
      func: Validators.requiredTrue
    },
    base64: {
      func: CustomValidators.base64,
      params: ["min"]
    },
    creditCard: {
      func: CustomValidators.creditCard
    },
    date: {
      func: CustomValidators.date
    },
    dateISO: {
      func: CustomValidators.dateISO
    },
    digits: {
      func: CustomValidators.digits
    },
    equal: {
      func: CustomValidators.equal,