routier-collection / core/src / Expression
Abstract Class: Expression
Defined in: core/src/expressions/types.ts:96
The base class for all expression types.
Extended by
EmptyExpressionNotParsableExpressionComparatorExpressionOperatorExpressionPropertyExpressionValueExpression
Constructors
Constructor
new Expression(
left?,right?):Expression
Defined in: core/src/expressions/types.ts:104
Parameters
left?
Expression
right?
Expression
Returns
Expression
Properties
type
abstractreadonlytype:ExpressionType
Defined in: core/src/expressions/types.ts:98
The type of the expression.
left?
optionalleft:Expression
Defined in: core/src/expressions/types.ts:100
The left-hand side of the expression (if applicable).
right?
optionalright:Expression
Defined in: core/src/expressions/types.ts:102
The right-hand side of the expression (if applicable).
Accessors
EMPTY
Get Signature
get
staticEMPTY():EmptyExpression
Defined in: core/src/expressions/types.ts:109
Returns
NOT_PARSABLE
Get Signature
get
staticNOT_PARSABLE():NotParsableExpression
Defined in: core/src/expressions/types.ts:113
Returns
Methods
isEmpty()
staticisEmpty(expression):boolean
Defined in: core/src/expressions/types.ts:117
Parameters
expression
Expression
Returns
boolean
isNotParsable()
staticisNotParsable(expression):boolean
Defined in: core/src/expressions/types.ts:121
Parameters
expression
Expression
Returns
boolean
toJson()
statictoJson(expression):SerializedExpression
Defined in: core/src/expressions/types.ts:147
Turns a tree into plain JSON, so a whole query can cross a wire.
On the class rather than beside it, because this is the type's own REPRESENTATION — there is one right answer and it belongs with the thing being represented, next to EMPTY and isEmpty. Rendering a tree into some other language (toSql, toMql, evaluate) is a different kind of thing: there are many, each belongs to its consumer, and none of them is canonical.
Why it is this small
Of the six node types a bound tree can contain, exactly one holds anything JSON cannot carry: PropertyExpression, whose live PropertyInfo has functions, a parent chain and caches. It reduces to a property PATH — PropertyInfo.id IS the dotted path, and getProperty is keyed by exactly that — so rebinding is one lookup.
ParamReferenceExpression never appears: it is a parse-time placeholder that binding replaces with a plain ValueExpression holding the resolved value. A serialized tree is always already bound, so there is no params object to send alongside it.
Switches on type rather than using the isXExpression guards, which live in ../assertions and import this module — the guards test the same discriminant, so nothing is lost.
Parameters
expression
Expression
Returns
fromJson()
staticfromJson(json,schema):Expression
Defined in: core/src/expressions/types.ts:211
Rebuilds a tree from JSON, rebinding every property against schema.
The schema is SUPPLIED rather than read out of the payload. A filter always belongs to a known collection, and the RECEIVER's schema is the authority on what its properties are — taking an id from the payload would mean rebinding against a schema the sender chose, which is backwards for anything crossing a trust boundary.
Parameters
json
schema
CompiledSchemaCore<any>
Returns
Expression
Throws
when a property path is not declared by schema. Not NOT_PARSABLE: on a receiver, a filter that silently stops filtering returns rows the requester excluded, which is the one failure here worse than an error.