New Generic Field Rewriter & Custom Rewriter #51
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| import { ASTNode } from 'graphql'; | ||
| import { NodeAndVarDefs } from '../ast'; | ||
| import Rewriter, { RewriterOpts, Variables } from './Rewriter'; | ||
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| interface CustomRewriterOpts extends RewriterOpts { | ||
| matchesFn?: (nodeAndVarDefs: NodeAndVarDefs, parents: ReadonlyArray<ASTNode>) => boolean; | ||
| rewriteQueryFn?: (nodeAndVarDefs: NodeAndVarDefs, variables: Variables) => NodeAndVarDefs; | ||
| rewriteVariablesFn?: (nodeAndVarDefs: NodeAndVarDefs, variables: Variables) => Variables; | ||
| rewriteResponseFn?: ( | ||
| response: any, | ||
| key: string, | ||
| index?: number, | ||
| nodeMatchAndParents?: ASTNode[] | ||
| ) => NodeAndVarDefs; | ||
| } | ||
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| /** | ||
| * A Custom rewriter with its Rewriter functions received as arguments. | ||
| * This Rewriter allows users to write their own rewriter functions. | ||
| */ | ||
| class CustomRewriter extends Rewriter { | ||
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| protected matchesFn: (nodeAndVarDefs: NodeAndVarDefs, parents: ReadonlyArray<ASTNode>) => boolean; | ||
| protected rewriteQueryFn: ( | ||
| nodeAndVarDefs: NodeAndVarDefs, | ||
| variables: Variables | ||
| ) => NodeAndVarDefs; | ||
| protected rewriteVariablesFn: (nodeAndVarDefs: NodeAndVarDefs, variables: Variables) => Variables; | ||
| protected rewriteResponseFn: ( | ||
| response: any, | ||
| key: string, | ||
| index?: number, | ||
| nodeMatchAndParents?: ASTNode[] | ||
| ) => NodeAndVarDefs; | ||
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| constructor(options: CustomRewriterOpts) { | ||
| const { | ||
| matchesFn, | ||
| rewriteQueryFn, | ||
| rewriteVariablesFn, | ||
| rewriteResponseFn, | ||
| matchConditions = [() => true], | ||
| ...rewriterOpts | ||
| } = options; | ||
| super({ ...rewriterOpts, matchConditions }); | ||
| this.matchesFn = matchesFn || super.matches; | ||
| this.rewriteQueryFn = rewriteQueryFn || super.rewriteQuery; | ||
| this.rewriteVariablesFn = rewriteVariablesFn || super.rewriteVariables; | ||
| this.rewriteResponseFn = rewriteResponseFn || super.rewriteResponse; | ||
| } | ||
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| public matches(nodeAndVarDefs: NodeAndVarDefs, parents: ReadonlyArray<ASTNode>): boolean { | ||
| return this.matchesFn(nodeAndVarDefs, parents); | ||
| } | ||
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| public rewriteQuery(nodeAndVarDefs: NodeAndVarDefs, variables: Variables) { | ||
| return this.rewriteQueryFn(nodeAndVarDefs, variables); | ||
| } | ||
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| public rewriteResponse( | ||
| response: any, | ||
| key: string, | ||
| index?: number, | ||
| nodeMatchAndParents?: ASTNode[] | ||
| ) { | ||
| return this.rewriteResponseFn(response, key, index, nodeMatchAndParents); | ||
| } | ||
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| public rewriteVariables(nodeAndVarDefs: NodeAndVarDefs, variables: Variables): Variables { | ||
| return this.rewriteVariablesFn(nodeAndVarDefs, variables); | ||
| } | ||
| } | ||
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| export default CustomRewriter; | ||
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| import { ArgumentNode, ASTNode, FieldNode, Kind, SelectionSetNode } from 'graphql'; | ||
| import { astArgVarNode, NodeAndVarDefs } from '../ast'; | ||
| import Rewriter, { RewriterOpts, Variables } from './Rewriter'; | ||
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| interface FieldRewriterOpts extends RewriterOpts { | ||
| newFieldName?: string; | ||
| arguments?: string[]; | ||
| objectFieldName?: string; | ||
| } | ||
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| /** | ||
| * More generic version of ScalarFieldToObjectField rewriter | ||
| */ | ||
| class FieldRewriter extends Rewriter { | ||
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There was a problem hiding this comment. This looks like it's doing the same thing as There was a problem hiding this comment. So, in addition to what the There was a problem hiding this comment. There's already There was a problem hiding this comment. So, adding arguments to a Field that has no initial arguments is missing, also argument value coercion I think is also lacking. There was a problem hiding this comment.
There was a problem hiding this comment. You're right FieldArgTypeRewriter has argument coercion. There was a problem hiding this comment. aah interesting I see what you mean about maybe needing to add an argument to make an old query valid in a new schema. That is a use-case that none of the current rewriters handle currently. Philosophically this library has favored small targeted rewriters for each use-case rather than 1 big one that does most things, but maybe this is a good change actually. For adding arguments, what do you think about making it a map instead of an array? ex There was a problem hiding this comment. Yes totally, that sounds even better |
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| protected newFieldName?: string; | ||
| protected arguments?: string[]; | ||
| protected objectFieldName?: string; | ||
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| constructor(options: FieldRewriterOpts) { | ||
| super(options); | ||
| this.newFieldName = options.newFieldName; | ||
| this.arguments = options.arguments; | ||
| this.objectFieldName = options.objectFieldName; | ||
| } | ||
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| public matches(nodeAndVars: NodeAndVarDefs, parents: ASTNode[]): boolean { | ||
| if (!super.matches(nodeAndVars, parents)) return false; | ||
| const node = nodeAndVars.node as FieldNode; | ||
| // if there's the intention of converting the field to a subselection | ||
| // make sure there's no subselections on this field | ||
| if (node.selectionSet && !!this.objectFieldName) return false; | ||
| return true; | ||
| } | ||
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| public rewriteQuery(nodeAndVarDefs: NodeAndVarDefs, variables: Variables) { | ||
| const node = nodeAndVarDefs.node as FieldNode; | ||
| const { variableDefinitions } = nodeAndVarDefs; | ||
| // if there's the intention of converting the field to a subselection | ||
| // and there's a subselection already, just return | ||
| if (node.selectionSet && !!this.objectFieldName) return nodeAndVarDefs; | ||
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| // if fieldName is meant to be renamed. | ||
| if (this.newFieldName) { | ||
| let newName = this.newFieldName; | ||
| if (this.newFieldName.includes(':')) { | ||
| const [alias, name] = this.newFieldName.split(':'); | ||
| newName = name.trim(); | ||
| Object.assign(node, { alias: { value: alias.trim(), kind: Kind.NAME } }); | ||
| } | ||
| Object.assign(node.name, { value: newName }); | ||
| } | ||
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| // if there's the intention of converting the field to a subselection | ||
| // of objectFieldNames assign SelectionSetNode to the field accordingly. | ||
| if (this.objectFieldName) { | ||
| const selectionSet: SelectionSetNode = { | ||
| kind: 'SelectionSet', | ||
| selections: [ | ||
| { | ||
| kind: 'Field', | ||
| name: { kind: 'Name', value: this.objectFieldName } | ||
| } | ||
| ] | ||
| }; | ||
| Object.assign(node, { selectionSet }); | ||
| } | ||
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| // If, 1) the field is a SelectionSet, | ||
| // 2) this.arguments is not empty nor undefined, and | ||
| // 3) query comes with variables, then assign ArgumentNodes to the field accordingly. | ||
| if (node.selectionSet && !!this.arguments && variables) { | ||
| // field may already come with some arguments | ||
| const newArguments: ArgumentNode[] = [...(node.arguments || [])]; | ||
| this.arguments.forEach(argName => { | ||
| if ( | ||
| this.isArgumentInVariables(argName, variables) && | ||
| !this.isArgumentInArguments(argName, newArguments) | ||
| ) { | ||
| newArguments.push(astArgVarNode(argName)); | ||
| } | ||
| }); | ||
| if (!!newArguments) Object.assign(node, { arguments: newArguments }); | ||
| } | ||
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| return { | ||
| variableDefinitions, | ||
| node | ||
| } as NodeAndVarDefs; | ||
| } | ||
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| public rewriteResponse(response: any, key: string, index?: number) { | ||
| // Extract the element we are working on | ||
| const element = super.extractReponseElement(response, key, index); | ||
| if (element === null) return response; | ||
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| let originalKey = key; | ||
| // if the key is found to be the renamed field | ||
| // then change the name of such field in the response | ||
| // and pass the new key (field name) down. | ||
| if (this.newFieldName) { | ||
| let newFieldName = this.newFieldName; | ||
| // the newFieldName may be alised. | ||
| if (this.newFieldName.includes(':')) { | ||
| const [alias] = this.newFieldName.split(':'); | ||
| newFieldName = alias.trim(); | ||
| } | ||
| if (key === newFieldName) { | ||
| if (this.fieldName) { | ||
| originalKey = this.fieldName; | ||
| Object.assign(response, { [originalKey]: response[key] }); | ||
| delete response[key]; | ||
| } | ||
| } | ||
| } | ||
| // Undo the nesting in the response so it matches the original query | ||
| let newElement = element; | ||
| if (this.objectFieldName) { | ||
| newElement = element[this.objectFieldName]; | ||
| } | ||
| return super.rewriteResponseElement(response, newElement, originalKey, index); | ||
| } | ||
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| private isArgumentInArguments(argName: string, argumentNodes: ArgumentNode[]) { | ||
| return argumentNodes.map(argNode => argNode.name.value).includes(argName); | ||
| } | ||
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| private isArgumentInVariables(argName: string, variables: Variables): boolean { | ||
| if (variables && Object.keys(variables).includes(argName)) return true; | ||
| return false; | ||
| } | ||
| } | ||
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| export default FieldRewriter; | ||
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