Support of 'when'

[mrpsiho]

Hi!

Many thanks for the useful library! I just want to ask if it is possible already but I am not aware of it or if it will be possible any time soon to include 'when' into json schema? I have to achieve this https://github.com/jquense/yup#mixedwhenkeys-string--arraystring-builder-object--value-schema-schema-schema somehow.

Thanks!

[MrLoh]

Could you provide an example for the input and output you expect.

[kristianmandrup]

Please add whatever you need. It should be structured to make it easy to extend as needed. Currently only supports "core" functionality, not all that JSON schema can express.

[mrpsiho]

Well, at least something simple like:

{
  "properties": {
    "name": {
      "type": "string"
    },
    "age": {
      "type": "number",
      "when": {
        "name": {
          "is": true,
          "then": "required"
        }
      }
    }
  }
}

What do you think of this?

[MrLoh]

It’s doable. Any pull requests are welcome. But no one can make promises when it will be implemented otherwise. I need to do some work on the library but there are some more pressing issues at first.

[kristianmandrup]

I will work on this today and add support for some basic conditions

[kristianmandrup]

Working on branch here: https://github.com/kristianmandrup/schema-to-yup/tree/when-condition

[kristianmandrup]

Should be enough foundation to finish simple support for when with then and otherwise.
See changes from previous commit.

[kristianmandrup]

Almost got a basic implementation working. Hope that helps you.
Just needs a little more debugging and testing...

[kristianmandrup]

See when.test.js

  describe("manual setup", () => {
    var inst = yup.object({
      isBig: yup.boolean(),
      count: yup.number().when("isBig", {
        is: true,
        then: yup.number().min(5),
        otherwise: yup.number().min(0)
      })
    });

    test("validate", () => {
      const result = inst.validateSync({
        isBig: true,
        count: 10
      });
      console.log({ result });

      expect(result).toBe(true);
    });
  });

  describe("use WhenCondition", () => {
    const { constraint } = whenCondition;

    console.log({ constraint });

    const count = yup.number().when(constraint);

    var inst = yup.object({
      isBig: yup.boolean(),
      count
    });

    test("validate", () => {
      const result = inst.validateSync({
        isBig: true,
        count: 10
      });

      console.log({ result });

      expect(result).toBe(true);
    });
  });

Just need to make when() function in mixed.js apply it correctly:

  when() {
    const when = this.constraints.when;
    if (!isObjectType(when)) return this;
    const { constraint } = this.createWhenConditionFor(when);

    if (!constraint) {
      this.warn(`Invalid when constraint for: ${when}`);
      return this;
    } else {
      this.logInfo(`Adding when constraint for ${this.key}`, constraint);
      // use buildConstraint or addConstraint to add when constraint (to this.base)

      this.addConstraint("when", { values: constraint, errName: "when" });
    }
    return this;
  }

[kristianmandrup]

This feature is ~90-95% done now.

[kristianmandrup]

Greatly improved design now. Major refactoring, loads of unit tests. Almost there ;)

[kristianmandrup]

Now all WhenEntry tests pass, which is the core of the feature functionality. Should be smooth sailing from here... Required extensive unit testing to get "just right".

[kristianmandrup]

Should be working now. Works in isolation with all tests passing.
Having a little "trouble" writing the correct schema + test combinations for using it in a full schema. Current tests all return valid results. Not sure why. Please check it out ;)

This can be used as a template/blueprint for adding similar, more advanced conditional logic!

# all tests pass
$ jest test/conditions/when-condition.test.js

# all tests pass
$ jest test/conditions/when-entry.test.js

# never invalid for current test/schema setup
$ jest test/schema-when-then.test.js

[kristianmandrup]

Now I'm adding tests for manual approach, then comparing with engine generated schema and result.

See test/schema-when-then.test.js

  describe("manual then", () => {
    const bigJson = {
      valid: {
        isBig: true,
        count: 5
      },
      invalid: {
        isBig: true,
        count: 4
      }
    };

    describe("simple", () => {
      const yupSchema = yup.object({
        isBig: yup.boolean(),
        count: yup.number().when("isBig", {
          is: true, // alternatively: (val) => val == true
          then: yup.number().min(5)
        })
      });

      const tester = createManualTester(yupSchema);

      test("valid", () => {
        tester(bigJson.valid, true);
      });

      test("invalid", () => {
        tester(bigJson.invalid, false);
      });
    });
  });

[kristianmandrup]

Finally works with the isBig example, both for manual and generated :)

[kristianmandrup]

Please test it out before I merge into master ;)

[kristianmandrup]

Released: schema-to-yup@1.9.0 on npm (note renamed to more generic name)