Mongoose: How to pass an other data with value to validation in mongoose schema?

[justin-john]

Pass an other data with value to validation function.

The following will be code for maxlength validation

maxLength = function  (v) {
    if (v && v.length) {
    return v.length <= 100;
    }
},

The schema field

desc: { type: String, validate: [maxLength, 'Exceed max length of 100 chars'] } 

Can we pass a data with validate?

i.e Like below code

desc: { type: String, validate: [maxLength, 100, 'Exceed max length of 100 chars'] } 


maxLength = function  (v, length) {
    if (v && v.length) {
    return v.length <= length;  // length will be 100
    }
},

Here validate second array element(length of desc) is passed to validation function. Later validate with this passed length.

How it can be accomplished?

[aheckmann]

What is the use case?

[justin-john]

@aheckmann I need a maximum length(maxlength) validator for String fields in schema. Each string fields have different maxlengths. So I need a common validator for maxlength with length of string need to be passed to validation function. So that I can control maxlength of different string fields from common validation function, not by writing different validation function for each String fields in schema.

[ebensing]

I think the best way to do this might be to just have a function which constructs your validator.
IE.

function getMaxValidator(val) {
  return function  (v) {
    if (v && v.length) {
      return v.length <= val;
    }
  }
}
// To get a validator for length 100, you'd do something like this
...
validate : getMaxValidator(100),
...

Pretty sure this should cover your use case here. If this doesn't work for you, let me know and we can reopen this.

[justin-john]

@ebensing How we can trigger the custom error message Exceed max length of 100 chars here?

[ebensing]

See the docs for how to pass custom error messages to validation functions.