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refactor: refactor and pass fpOptions for fhirpath expr
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@ruscoder
ruscoder committed May 25, 2024
1 parent 4809e3d commit 19f4970
Showing 1 changed file with 125 additions and 42 deletions.
167 changes: 125 additions & 42 deletions ts/server/src/utils/extract.ts
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Original file line number Diff line number Diff line change
@@ -1,13 +1,30 @@
import { Resource } from 'fhir/r4b';
import * as fhirpath from 'fhirpath';

type Resource = Record<string, any>;


type UserInvocationTable = {
[name: string]: {
fn: (...args: any) => any,
arity: {
[numberOfParams: number]: Array<'Expr' | 'AnyAtRoot' | 'Identifier' | 'TypeSpecifier' | 'Any' | 'Integer' | 'Boolean' | 'Number' | 'String'>
},
nullable?: boolean,
internalStructures?: boolean
}
};

interface FPOptions {
// userInvocationTable?: UserInvocationTable;
}

interface Embedded {
before: string;
after: string;
expression: string;
}

// TODO rewrite using regex and multiple embedding
// TODO rewrite using regex and multiple embedding (#8)
export function embeddedFHIRPath(a: string): Embedded | undefined {
const start = a.search('{{');
const stop = a.search('}}');
Expand All @@ -25,27 +42,43 @@ export function embeddedFHIRPath(a: string): Embedded | undefined {
};
}

export function resolveTemplate(qr: Resource, template: any, context?: any, model?: Model): any {
return resolveTemplateRecur(qr, { rootNode: template }, context, model)['rootNode'];
export function resolveTemplate(
resource: Resource,
template: any,
context?: Context,
model?: Model,
fpOptions?: FPOptions,
): any {
// We pass template under rootNode because template might be not object, e.g. array or primitive
return resolveTemplateRecur(resource, { rootNode: template }, context, model, fpOptions)[
'rootNode'
];
}

function resolveTemplateRecur(
resource: Resource,
template: any,
initialContext: object,
model: Model,
initialContext?: Context,
model?: Model,
fpOptions?: FPOptions,
): any {
return iterateObject(template, initialContext, (node, context) => {
return iterateObject(template, initialContext?? {}, (node, context) => {
if (isPlainObject(node)) {
const { node: newNode, context: newContext } = processAssignBlock(
resource,
node,
context,
model,
fpOptions,
);
const matchers = [matchForBlock, matchContextBlock, matchIfBlock, matchMergeBlock];
const matchers = [
processForBlock,
processContextBlock,
processIfBlock,
processMergeBlock,
];
for (const matcher of matchers) {
const result = matcher(resource, newNode, newContext, model);
const result = matcher(resource, newNode, newContext, model, fpOptions);

if (result) {
return { node: result.node, context: newContext };
Expand All @@ -58,7 +91,13 @@ function resolveTemplateRecur(

if (embedded) {
const result =
fhirpath.evaluate(resource, embedded.expression, context, model)[0] ?? null;
fhirpath.evaluate(
resource,
embedded.expression,
context,
model,
fpOptions,
)[0] ?? null;
if (embedded.before || embedded.after) {
return {
node: `${embedded.before}${result}${embedded.after}`,
Expand All @@ -77,7 +116,13 @@ function resolveTemplateRecur(
});
}

function processAssignBlock(resource: Resource, node: any, context: any, model: any) {
function processAssignBlock(
resource: Resource,
node: any,
context: Context,
model: Model,
fpOptions: FPOptions,
): { node: any; context: Context } {
const extendedContext = { ...context };
const keys = Object.keys(node);

Expand All @@ -86,15 +131,15 @@ function processAssignBlock(resource: Resource, node: any, context: any, model:
if (assignKey) {
if (Array.isArray(node[assignKey])) {
node[assignKey].forEach((obj) => {
Object.entries(resolveTemplate(resource, obj, extendedContext, model)).forEach(
([key, value]) => {
extendedContext[key] = value;
},
);
Object.entries(
resolveTemplate(resource, obj, extendedContext, model, fpOptions),
).forEach(([key, value]) => {
extendedContext[key] = value;
});
});
} else if (isPlainObject(node[assignKey])) {
Object.entries(
resolveTemplate(resource, node[assignKey], extendedContext, model),
resolveTemplate(resource, node[assignKey], extendedContext, model, fpOptions),
).forEach(([key, value]) => {
extendedContext[key] = value;
});
Expand All @@ -108,7 +153,13 @@ function processAssignBlock(resource: Resource, node: any, context: any, model:
return { node, context };
}

function matchForBlock(resource: Resource, node: any, context: any, model: any) {
function processForBlock(
resource: Resource,
node: any,
context: Context,
model: Model,
fpOptions: FPOptions,
): { node: any } | undefined {
const keys = Object.keys(node);

const forRegExp = /{%\s*for\s+(?:(\w+?)\s*,\s*)?(\w+?)\s+in\s+(.+?)\s*%}/;
Expand All @@ -124,7 +175,7 @@ function matchForBlock(resource: Resource, node: any, context: any, model: any)
const itemKey = hasIndexKey ? matches[2] : matches[1];
const expr = hasIndexKey ? matches[3] : matches[2];

const answers = fhirpath.evaluate(resource, expr, context, model);
const answers = fhirpath.evaluate(resource, expr, context, model, fpOptions);
return {
node: answers.map((answer, index) =>
resolveTemplate(
Expand All @@ -136,13 +187,20 @@ function matchForBlock(resource: Resource, node: any, context: any, model: any)
...(hasIndexKey ? { [indexKey]: index } : {}),
},
model,
fpOptions,
),
),
};
}
}

function matchContextBlock(resource: Resource, node: any, context: any, model: any) {
function processContextBlock(
resource: Resource,
node: any,
context: Context,
model: Model,
fpOptions: FPOptions,
): { node: any } | undefined {
const keys = Object.keys(node);

const contextRegExp = /{{\s*(.+?)\s*}}/;
Expand All @@ -154,42 +212,54 @@ function matchContextBlock(resource: Resource, node: any, context: any, model: a
const matches = contextKey.match(contextRegExp);

const expr = matches[1];
const answers = fhirpath.evaluate(resource, expr, context, model);
const answers = fhirpath.evaluate(resource, expr, context, model, fpOptions);
const result: any[] = answers.map((answer) =>
resolveTemplate(answer, node[contextKey], context, model),
resolveTemplate(answer, node[contextKey], context, model, fpOptions),
);

return { node: result };
}
}

function matchMergeBlock(resource: Resource, node: any, context: any, model: any) {
function processMergeBlock(
resource: Resource,
node: any,
context: Context,
model: Model,
fpOptions: FPOptions,
): { node: any } | undefined {
const keys = Object.keys(node);

const mergeRegExp = /{%\s*merge\s*%}/;
const mergehKey = keys.find((k) => k.match(mergeRegExp));
if (mergehKey) {
const mergeKey = keys.find((k) => k.match(mergeRegExp));
if (mergeKey) {
if (keys.length > 1) {
throw new Error('Merge block must be presented as single key');
}

return {
node: (Array.isArray(node[mergehKey]) ? node[mergehKey] : [node[mergehKey]]).reduce(
node: (Array.isArray(node[mergeKey]) ? node[mergeKey] : [node[mergeKey]]).reduce(
(mergeAcc, nodeValue) => {
const result = resolveTemplate(resource, nodeValue, context, model);
const result = resolveTemplate(resource, nodeValue, context, model, fpOptions);
if (!isPlainObject(result) && result !== null) {
throw new Error('Merge block must contain object');
}

return { ...mergeAcc, ...(result || {}) };
},
omitKey(node, mergehKey),
{},
),
};
}
}

function matchIfBlock(resource: Resource, node: any, context: any, model: any) {
function processIfBlock(
resource: Resource,
node: any,
context: Context,
model: Model,
fpOptions: FPOptions,
): { node: any } | undefined {
const keys = Object.keys(node);

const ifRegExp = /{%\s*if\s+(.+?)\s*%}/;
Expand All @@ -207,37 +277,42 @@ function matchIfBlock(resource: Resource, node: any, context: any, model: any) {
const matches = ifKey.match(ifRegExp);
const expr = matches[1];

const answer = fhirpath.evaluate(resource, `iif(${expr}, true, false)`, context, model)[0];
const answer = fhirpath.evaluate(
resource,
`iif(${expr}, true, false)`,
context,
model,
fpOptions,
)[0];

return {
node: answer
? resolveTemplate(resource, node[ifKey], context, model)
? resolveTemplate(resource, node[ifKey], context, model, fpOptions)
: elseKey
? resolveTemplate(resource, node[elseKey], context, model)
? resolveTemplate(resource, node[elseKey], context, model, fpOptions)
: null,
};
}
}

type Transformer = (node: any, context: any) => { node: any; context: any };
type Transformer = (node: any, context: Context) => { node: any; context: Context };

function iterateObject(obj: any, context: any, transform: Transformer): any {
function iterateObject(obj: any, context: Context, transform: Transformer): any {
if (Array.isArray(obj)) {
// Arrays are flattened and null values are removed here
return obj
.flatMap((value) => {
const { node: newNode, context: newContext } = transform(value, context);
const result = transform(value, context);

return iterateObject(newNode, newContext, transform);
return iterateObject(result.node, result.context, transform);
})
.filter((x) => x !== null);
} else if (isPlainObject(obj)) {
return Object.fromEntries(
Object.entries(obj).map(([key, value]) => {
const { node: newNode, context: newContext } = transform(value, context);
return mapValues(obj, (value) => {
const result = transform(value, context);

return [key, iterateObject(newNode, newContext, transform)];
}),
);
return iterateObject(result.node, result.context, transform);
});
}

return transform(obj, context).node;
Expand All @@ -247,6 +322,14 @@ function isPlainObject(obj: any) {
return Object.prototype.toString.call(obj) === '[object Object]';
}

function mapValues(obj: object, fn: (value: any, key: string) => any) {
return Object.fromEntries(
Object.entries(obj).map(([key, value]) => {
return [key, fn(value, key)];
}),
);
}

function omitKey(obj: any, key: string) {
// eslint-disable-next-line @typescript-eslint/no-unused-vars
const { [key]: _, ...rest } = obj;
Expand Down

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