Allow pattern to also work with number/integer type

[caub]

What version of Ajv you are you using?
Latest: 8.12.0

What problem do you want to solve?
pattern prop is ignored if type is number for example

What do you think is the correct solution to problem?
pattern should still be used, as for example regex.test(value) works if value is a string or number, it's automatically stringified

Will you be able to implement it?
probably

Code summary

const Ajv = require('ajv').default;

const ajv = new Ajv({
  coerceTypes: true,
});
const schema = {
  type: 'object',
  properties: {
    price: {
      type: 'number',
      pattern: '^-?\\d+(\\.\\d{1,2})?$'
    }
  }
};
// this shouldn't be valid, yet it is
console.log(
  ajv.validate(schema, { price: '123.005' }),
  ajv.errors,
);

Of course it's possible to add a custom keyword to get it working, but would be great if it works in the core

[jasoniangreen]

The data is valid because you have coerceTypes which changes it to a number and then with number the pattern keyword is ignored. I don't see this being something we would consider changing as it is defined by the JSON Schema standard in this way.

[sebix]

In principle what you are trying to achieve (the limit the precision of a number) should be possible with multipleOf, but that shows interesting behavior:

const schema = {
  type: 'object',
  properties: {
    price: {
      type: 'number',
      multipleOf: 0.01
    }
  }
};
const validate = ajv.compile(schema)
function test(data) {
  const valid = validate(data)
  if (valid) console.log(data.price + " is valid!")
  else console.log(data.price + " is invalid: " + ajv.errorsText(validate.errors))
}

test({price: 10.04})
// "10.04 is invalid: data/price must be multiple of 0.01"
test({price: -10.06})
// "-10.06 is valid!"
test({price: 123.005})
// "123.005 is invalid: data/price must be multiple of 0.01"

[sebix]

Ah, @caub: just use

const ajv = new Ajv({
    allErrors: true,
    multipleOfPrecision: 2
})

then multipleOf: 0.01 works fine.

Found via #84, #2416 and #652 the latter also has alternative solutions.

[caub]

@sebix it doesn't work for 123.50001 for example, see: https://replit.com/@caub/ajv-currency#index.js