quick validation/filtering of objects and http params against a schema
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schemajs Build Status

validate objects (including http request params) against a schema. includes express middleware.


npm install schemajs


  • validates schema for deep objects and arrays as well
  • schema is in JSON, making it portable
  • properties, types and filters are extensible

EXAMPLE USAGE - validate an object

var schema  = require("./path/to/schemajs");
var model   = schema.create(
  name:	   {type:"string", filters:"trim", properties:{max:255}, required:true},
  email:   {type:"email", filters:"trim", required:true},
  wins:    {type:"int", filters:["trim", "toInt"], default:0},
  average: {type:"float", filters:["trim", "toFloat"], default:0}

var form = model.validate({name:" your name ", email:" [email protected] "});

// form.valid  - boolean, true if object matches schema
//   - contains filtered version of the object {name:"your name", email:"[email protected]", wins:0, average:0}
// form.errors - contains associative array of any errors found

If you pass {strict: true} as additional arguments into Schema#validate, the validation will fail if there are additional keys in the object which are not defined in the schema.

EXAMPLE USAGE - in expressjs, validate the request parameters

var schema  = require("./path/to/schemajs");
var query   = schema.create(
  wins:    {type:"int", filters:"toInt"},
  query:   {type:"string", filters:"trim", required:true, error:"invalid query"}

app.get("/users", schema.middleware(query), function(req, res)
  // schema validation is attached to req.form
    db_lookup({, wins:});
    next(new Error("invalid request"));
    //next(req.form.errors, 400);



quickly test an individual schema

field = schema.test("em[email protected]", {type:"email", trim:true, properties:{min:5}});


schema for a simple object of one integer value

schema =
         // [string] value for acceppted parameters of the object you want to test
    // [string (built in types) or function (custom types)] the type declaration for accepted values
    "type": "int",
    // [string (built in filters) or function (custom filters) or array (mix and match!)] 
    // OPTIONAL, filters to process and optionally modify values
    "filters": ["trim", "toInt", custom_filter],
    // [anything] 
    // OPTIONAL, the default value if none is supplied by the object
    "default": 0,
    // [boolean] 
    // OPTIONAL, if true, this parameter must exist to validate
    "required": true,

    // [boolean] 
    // OPTIONAL, if true, this parameter can be null, despite any other rules
    "allownull": true,
    // [object] 
    // OPTIONAL, functions are custom property checks, else a built in property will be looked up
    "properties": {max:100, min:0, special:custom_property},
    // [string, object] OPTIONAL, if there is an error, you can override the message that is returned
    // use a string or the "default" key to use the default error message
    // keys can be any property key that was used as well as "filters", "required", "type"
    "error": {max: "too many wins", min: "too few wins", "default": "something is wrong with your wins value"}

schema with embedded schemas for object and array types

schema =
    "type":  "object",
      "name":  { type: "string", properties: { max: 255 }, required: true},
      "email": { type: "email", error: "email is not a valid email address"}
    "error": "user needs an email and a name"
    "type":  "array",
      "type": "string"
    "properties":  { max: 10, min: 3},
    "error": { max: "too many tags", min: "too few tags" }


built in types

[string+, string (empty string allowed), alpha, alphanum, email, object, array, date, number, int, boolean, url, zipcode]

to extend, add a function onto schema.types that accepts a value and returns a boolean if the type matches

test is run AFTER schema.filters are run

schema.types.awesome = function(value)
    return true;
    return false;


built in filters:

[toInt, toFloat, toString, toDate, toBoolean (converts on/off, true/false, 1/0, yes/no to bools), trim, lowercase, uppercase]

to extend, add a function onto schema.filters that takes in a value and returns the updated value

filters are run BEFORE schema.test is run

schema.filters.surround = function(value)
  if(value == needs_surrounding)
    return "----" + value + "----";
    return value;

built in properties

[max, min, regex, in]

to extend, add a function onto that takes in a value and any additional arguments

properties are run AFTER test and filters = function(value)
  if(isArray(value) && allUnique(value))
    return true;
    return false;
} = function(value, badwords)
  if(badwords.indexOf(value) != -1)
    return false;
    return true;

Browser usage

You can use it in the browser by using browserify, however if that's too much work just use There is also an example <examples/cdn.html>


  • dependency property making one parameters existance depend on another
  • more types (phone numbers, credit card, ip address)
  • more filters (camelcase, encode/unencode)
  • more properties
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