kapv89/shape

Isomorphic & async object-validation library for JS

shape

Isomorphic and Async object validation library.

npm install --save @krab/shape'

import Shape from '@krab/shape'

const Shape = require('@krab/shape/common')

shape is used to vaidate data in an async manner. Doesn't matter if your checks are all synchronous, shape will check them in an async manner. This is very useful for validating data against external data sources. Example below:

import Shape from '@krab/shape';

// using async-await
async function createUser(data={}) {
  const validation = new Shape({
    username: async (username) => {
      if (isString(username) && username.length > 0) {
        const existing = await findUserByUsername(username);
        return existing ? 'username taken' : null;
      } else {
        return 'invalid';
      }
    },

    password: (password) => {
      return isString(password) && password.length >= 7 ? null : 'invalid';
    },

    repeat_password: (repeat_password, {password}) => {
      return repeat_password === password ? null : 'invalid';
    }
  });

  const errors = await validation.errors(data);
  // Errors will be 'null' if all checks pass.
  // If any check fails, errors will be an object that contains error messages.
  // Validation will also fail for keys in data which are not specified when
  // defining a validation

  if (errors) {
    throw errors;
  } else {
    return await insertNewPostInDB(data);
  }
}

// using promises
function createPost(data={}) {
  const validation = new Shape({
    author_id: async (authorId) => {
      const author = await findUserById(authorId);
      return author ? null : `invalid author_id: ${authorId}`;
    },

    title: (title) => {
      return isString(title) ? findPostByTitle(title).then((existing) => {
        return (
          existing ? 'title already taken' : (
            title.length === 0 ? 'title cannot be empty' : null
          )
        );
      }) : 'title must be string';
    },

    body: (body) => {
      if (!isArray(body) || body.filter((p) => isString(p)).length < body.length) {
        return 'body must be a list of paragraph strings';
      } else if (body.length === 0) {
        return 'body cannot be empty';
      } else {
        return null;
      }
    }
  });

  return validation.errors(data).then((errors) => {
    if (errors) {
      return Promise.reject(errors);
    } else {
      return insertNewPostInDB(data);
    }
  });
}