demo/typescript.js
function getTypeForVariableLikeDeclaration(declaration) {
            // A variable declared in a for..in statement is always of type any
            if (declaration.parent.parent.kind === 200 /* ForInStatement */) {
                return anyType;
            }
            if (declaration.parent.parent.kind === 201 /* ForOfStatement */) {
                // checkRightHandSideOfForOf will return undefined if the for-of expression type was
                // missing properties/signatures required to get its iteratedType (like
                // [Symbol.iterator] or next). This may be because we accessed properties from anyType,
                // or it may have led to an error inside getElementTypeOfIterable.
                return checkRightHandSideOfForOf(declaration.parent.parent.expression) || anyType;
            }
            if (ts.isBindingPattern(declaration.parent)) {
                return getTypeForBindingElement(declaration);
            }
            // Use type from type annotation if one is present
            if (declaration.type) {
                return getTypeFromTypeNode(declaration.type);
            }
            if (declaration.kind === 138 /* Parameter */) {
                var func = declaration.parent;
                // For a parameter of a set accessor, use the type of the get accessor if one is present
                if (func.kind === 146 /* SetAccessor */ && !ts.hasDynamicName(func)) {
                    var getter = ts.getDeclarationOfKind(declaration.parent.symbol, 145 /* GetAccessor */);
                    if (getter) {
                        return getReturnTypeOfSignature(getSignatureFromDeclaration(getter));
                    }
                }
                // Use contextual parameter type if one is available
                var type = getContextuallyTypedParameterType(declaration);
                if (type) {
                    return type;
                }
            }
            // Use the type of the initializer expression if one is present
            if (declaration.initializer) {
                return checkExpressionCached(declaration.initializer);
            }
            // If it is a short-hand property assignment, use the type of the identifier
            if (declaration.kind === 246 /* ShorthandPropertyAssignment */) {
                return checkIdentifier(declaration.name);
            }
            // If the declaration specifies a binding pattern, use the type implied by the binding pattern
            if (ts.isBindingPattern(declaration.name)) {
                return getTypeFromBindingPattern(declaration.name, /*includePatternInType*/ false);
            }
            // No type specified and nothing can be inferred
            return undefined;
        }
function getTypeForVariableLikeDeclaration(declaration) {
            // A variable declared in a for..in statement is always of type any
            if (declaration.parent.parent.kind === 200 /* ForInStatement */) {
                return anyType;
            }
            if (declaration.parent.parent.kind === 201 /* ForOfStatement */) {
                // checkRightHandSideOfForOf will return undefined if the for-of expression type was
                // missing properties/signatures required to get its iteratedType (like
                // [Symbol.iterator] or next). This may be because we accessed properties from anyType,
                // or it may have led to an error inside getElementTypeOfIterable.
                return checkRightHandSideOfForOf(declaration.parent.parent.expression) || anyType;
            }
            if (ts.isBindingPattern(declaration.parent)) {
                return getTypeForBindingElement(declaration);
            }
            // Use type from type annotation if one is present
            if (declaration.type) {
                return getTypeFromTypeNode(declaration.type);
            }
            if (declaration.kind === 138 /* Parameter */) {
                var func = declaration.parent;
                // For a parameter of a set accessor, use the type of the get accessor if one is present
                if (func.kind === 146 /* SetAccessor */ && !ts.hasDynamicName(func)) {
                    var getter = ts.getDeclarationOfKind(declaration.parent.symbol, 145 /* GetAccessor */);
                    if (getter) {
                        return getReturnTypeOfSignature(getSignatureFromDeclaration(getter));
                    }
                }
                // Use contextual parameter type if one is available
                var type = getContextuallyTypedParameterType(declaration);
                if (type) {
                    return type;
                }
            }
            // Use the type of the initializer expression if one is present
            if (declaration.initializer) {
                return checkExpressionCached(declaration.initializer);
            }
            // If it is a short-hand property assignment, use the type of the identifier
            if (declaration.kind === 246 /* ShorthandPropertyAssignment */) {
                return checkIdentifier(declaration.name);
            }
            // If the declaration specifies a binding pattern, use the type implied by the binding pattern
            if (ts.isBindingPattern(declaration.name)) {
                return getTypeFromBindingPattern(declaration.name, /*includePatternInType*/ false);
            }
            // No type specified and nothing can be inferred
            return undefined;
        }
Return the inferred type for a variable, parameter, or property declaration