--- /dev/null
+import type {
+ CodeKeywordDefinition,
+ ErrorObject,
+ KeywordErrorDefinition,
+ AnySchema,
+} from "../../types"
+import type {SchemaObjCxt} from "../../compile"
+import type {KeywordCxt} from "../../compile/validate"
+import {_, str, not, Name} from "../../compile/codegen"
+import {alwaysValidSchema, checkStrictMode} from "../../compile/util"
+
+export type IfKeywordError = ErrorObject<"if", {failingKeyword: string}, AnySchema>
+
+const error: KeywordErrorDefinition = {
+ message: ({params}) => str`must match "${params.ifClause}" schema`,
+ params: ({params}) => _`{failingKeyword: ${params.ifClause}}`,
+}
+
+const def: CodeKeywordDefinition = {
+ keyword: "if",
+ schemaType: ["object", "boolean"],
+ trackErrors: true,
+ error,
+ code(cxt: KeywordCxt) {
+ const {gen, parentSchema, it} = cxt
+ if (parentSchema.then === undefined && parentSchema.else === undefined) {
+ checkStrictMode(it, '"if" without "then" and "else" is ignored')
+ }
+ const hasThen = hasSchema(it, "then")
+ const hasElse = hasSchema(it, "else")
+ if (!hasThen && !hasElse) return
+
+ const valid = gen.let("valid", true)
+ const schValid = gen.name("_valid")
+ validateIf()
+ cxt.reset()
+
+ if (hasThen && hasElse) {
+ const ifClause = gen.let("ifClause")
+ cxt.setParams({ifClause})
+ gen.if(schValid, validateClause("then", ifClause), validateClause("else", ifClause))
+ } else if (hasThen) {
+ gen.if(schValid, validateClause("then"))
+ } else {
+ gen.if(not(schValid), validateClause("else"))
+ }
+
+ cxt.pass(valid, () => cxt.error(true))
+
+ function validateIf(): void {
+ const schCxt = cxt.subschema(
+ {
+ keyword: "if",
+ compositeRule: true,
+ createErrors: false,
+ allErrors: false,
+ },
+ schValid
+ )
+ cxt.mergeEvaluated(schCxt)
+ }
+
+ function validateClause(keyword: string, ifClause?: Name): () => void {
+ return () => {
+ const schCxt = cxt.subschema({keyword}, schValid)
+ gen.assign(valid, schValid)
+ cxt.mergeValidEvaluated(schCxt, valid)
+ if (ifClause) gen.assign(ifClause, _`${keyword}`)
+ else cxt.setParams({ifClause: keyword})
+ }
+ }
+ },
+}
+
+function hasSchema(it: SchemaObjCxt, keyword: string): boolean {
+ const schema = it.schema[keyword]
+ return schema !== undefined && !alwaysValidSchema(it, schema)
+}
+
+export default def