To use it, npm install fhirpath.js. Then:
var fp = require('fhirpath.js')
var result = fp.evaluate({ // the target to evaluate against
"a": 1,
"b": [2, 3]
}, "a | b | a") // the path expression to evaluate
assert.deepEqual(result, [1, 2, 3, 1])To add you own custom constants to the lookup table, pass along a third argument like:
var result = fp.evaluate({ // the target to evaluate against
"a": "some great value",
"b": [2, 3]
}, "a=%my-constant", {
"my-constant": "some great value"
})
assert.deepEqual(result, [true])If passing a lookup table with every call gets tedious, you can create a new execution context with the table baked in:
var myfp = fp.withConstants({"my-constant": "some great value"})
var result = myfp.evaluate({ // the target to evaluate against
"a": "some great value",
"b": [2, 3]
}, "a=%my-constant")
assert.deepEqual(result, [true])Live demo at https://niquola.github.io/fhirpath-demo/#/
Generate the lexer and parser from the included Antlr grammer via:
sh ./setup.sh
Run tests:
npm test
Regenerate test case file:
npm run-script generate-test-cases
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