esvalid

Install

npm install esvalid

Usage

esvalid.isValid(node) :: Spidermonkey AST Node → Boolean

Returns true if and only if the given AST node represents a valid ECMAScript program.

esvalid.isValidExpression(node) :: Spidermonkey AST Node → Boolean

Returns true if and only if the given AST node represents a valid ECMAScript expression.

esvalid.errors(node) :: Spidermonkey AST Node → [InvalidAstError]

Returns an array of InvalidAstError objects representing the errors in the given AST. An effort is made to continue collecting errors in the face of malformed ASTs. If an empty array is returned, it is implied that the given AST node is error free.

new esvalid.InvalidAstError(node, message) :: Node -> String -> InvalidAstError

Constructs a new InvalidAstError instance. node must be non-null.

Example

var esvalid = require("esvalid");
var esprima = require("esprima");

var program = esprima.parse(fs.readFileSync(require.resolve("esprima")));
esvalid.isValid(program); // true

esvalid.isValid({type: "Program", body: []}); // true
esvalid.isValid({type: "Program", body: null}); // false

esvalid.isValidExpression({type: "Program", body: []}); // false
esvalid.isValidExpression({type: "Literal", value: 0}); // true

esvalid.errors({type: "Program", body: []}); // []
var error = esvalid.errors({type: "Program", body: null})[0];
error instanceof esvalid.InvalidAstError; // true
error.node; // {type: "Program", body: null}
error.message; // "Program `body` member must be non-null"

Validity Tests

This is a list of all esvalid validity tests other than null tests and type checks.

• BreakStatement must have an IterationStatement or SwitchStatement as an ancestor
• labelled BreakStatement must have a matching LabeledStatement ancestor
• ContinueStatement must have an IterationStatement as an ancestor
• labelled ContinueStatement must have a matching LabeledStatement ancestor
• Identifier name member must be a valid IdentifierName
• Identifier name member must not be a ReservedWord
• IfStatement with null alternate must not be the consequent of an IfStatement with a non-null alternate
• LabeledStatement must not be nested within a LabeledStatement with the same label
• numeric Literal nodes must not be NaN
• numeric Literal nodes must be non-negative
• numeric Literal nodes must be finite
• static MemberExpression property member must have a valid IdentifierName name member
• ObjectExpression getter property value member must have zero parameters
• ObjectExpression setter property value member must have exactly one parameter
• ObjectExpression must not have more than one data property with the same name in strict mode
• ObjectExpression must not have data and getter properties with the same name
• ObjectExpression must not have data and setter properties with the same name
• ObjectExpression must not have data and getter properties with the same name
• ObjectExpression must not have multiple getters with the same name
• ObjectExpression must not have data and setter properties with the same name
• ObjectExpression must not have multiple setters with the same name
• ReturnStatement must be nested within a FunctionExpression or FunctionDeclaration node
• SequenceExpression expressions member length must be >= 2
• SwitchStatement cases member must contain no more than one SwitchCase with a null test member
• TryStatement must have a non-null handler member or a non-null finalizer member
• delete with unqualified identifier not allowed in strict mode
• VariableDeclaration declarations member must be non-empty
• WithStatement not allowed in strict mode