Constructor
new Stitcher(options)
Parameters:
| Name |
Type |
Description |
options |
object
|
options for interacting with the graphql data source.
Properties
| Name |
Type |
Attributes |
Default |
Description |
schema |
object
|
|
|
an executable schema providing access to the graphql data source,
possibly created via use of makeExecutableSchema or makeRemoteExecutableSchema from the
graphql-tools package. |
transforms |
Array.<object>
|
<optional>
|
|
additional transforms to be added on schema delegation.
Transforms can be added here on initial Stitcher creation or later on a per "stitch" basis. |
preStitchFragmentName |
string
|
<optional>
|
PreStitch
|
a string representing the fragment
name for the pseudo-fragment representing the pre-"stitch" selection set, to be used in
conjunction with the selectionSet option within the "from" and "to" methods. |
|
Examples
// execute query on targetSchema directly without working from current
// info object.
myStitcher.execute({operation, fieldName, selectionSet, args})
// stitch current query to targetSchema, i.e. pass the remaining
// selectionSet to the target schema
myStitcher.from(info).delegateTo({operation, fieldName, args})
// stitch current query to targetSchema, transform prior to delegation
myStitcher.from(info).transform({selectionSet, result}).delegateTo({operation, fieldName, args})
// For code re-use:
// 1. derive a custom Stitcher class from the base Stitcher class
// 2. add a custom delegator with any required transforms
myStitcher.from(info).delegateToFieldWithTransforms(args)
Methods
delegateTo(options) → {Promise}
Delegates to the configured target schema.
Parameters:
| Name |
Type |
Description |
options |
object
|
options for schema delegation to the specified target field.
Properties
| Name |
Type |
Attributes |
Description |
operation |
string
|
|
one of 'query', 'mutation', or 'subscription'. |
fieldName |
string
|
|
root field name on target schema. |
args |
object
|
<optional>
|
named arguments for the query. |
transforms |
Array.<object>
|
<optional>
|
additional transforms to be added for this "stitch." |
|
Returns:
a promise that will resolve to the graphql result.
-
Type
-
Promise
execute(options) → {Promise}
Directly executes a query without stitching an info object.
Parameters:
| Name |
Type |
Description |
options |
object
|
options for schema delegation to the specified target field.
Properties
| Name |
Type |
Attributes |
Description |
operation |
string
|
|
one of 'query', 'mutation', or 'subscription'. |
fieldName |
string
|
|
root field name on target schema. |
args |
object
|
<optional>
|
named arguments for the query. |
selectionSet |
string
|
object
|
function
|
<optional>
|
a selection set specified as graphql SDL
or as an AST. |
result |
function
|
<optional>
|
an optional function to transform the result. |
transforms |
Array.<object>
|
<optional>
|
additional transforms to be added for this "stitch." |
|
Returns:
a promise that will resolve to the graphql result.
-
Type
-
Promise
from(infoopt, optionsopt) → {Stitcher}
Creates a new Stitcher object based on the original Stitcher object settings. This function is
designed to allow adding the query information prior to stitching. It takes a single parameter,
either an info object or an options object with the info property set. When specifying no other
options, one can pass the info object itself instead of the options object.
Parameters:
| Name |
Type |
Attributes |
Description |
info |
object
|
<optional>
|
a graphql info object providing information about the query execution. |
options |
object
|
<optional>
|
an options object with an info property set to the graphql info object.
Properties
| Name |
Type |
Attributes |
Description |
info |
object
|
|
a graphql info object providing information about the query
execution. |
context |
object
|
<optional>
|
a graphql context object to be passed to the executable schema.
If the Stitcher class is used as a datasource, the context will be automatically provided on data
source initialization, but can be overridden. |
|
Returns:
a Stitcher object instance for chaining.
-
Type
-
Stitcher
Transform the selection set prior to delegation. Options can be specified to transform the
requested selection set prior to delegation and/or to reverse the transformation on receipt of
the result. Multiple transformations can be performed; selection set transformations are applied
sequentially, while result tranformation reversals are processed in reverse order.
Parameters:
| Name |
Type |
Description |
options |
object
|
options for selectionSet transformation.
Properties
| Name |
Type |
Attributes |
Description |
selectionSet |
string
|
object
|
function
|
|
a selection set specified as graphql SDL
or as an AST, in which references to a pseudo-fragment named PreStitch will be expanded with the
pre-"stitch" selection set. Alternatively, selectionSet may represent a function that takes the
pre-"stitch" selection set AST as an argument and returns a post-"stitch" selection set. For
example, a selection set can be specified to wrap fields prior to delegation, or to add fields. |
result |
function
|
<optional>
|
an optional function to reverse the transformation. For
example, if the selection set transformation involves wrapping the selection set prior to
delegation, this option can be used to automatically unwrap the result. |
|
Returns:
a Stitcher object instance for chaining.
-
Type
-
Stitcher
Example
myStitcher.from(info).transform({selectionSet, result}).delegateTo({operation, fieldName, args})
*