![\"@sagold/json-query\"](\"./docs/sagold-json-query.png\")
json-query lets you quickly select values, patterns or types from json-data. Its input requires a simple string, describing a concise query into your data.
\n Features | Introduction | Api | About patterns | Further examples | Breaking changes\n
\n\n**install**\n\n`yarn add @sagold/json-query`\n\n\n## Features\n\n- [json-pointer](https://github.com/sagold/json-pointer) syntax `#/list/0/id`\n- glob-patterns for properties (`*`, `**`)\n- regex-support for properties `{any.*}`\n- pattern-support for inifinite recursion `/tree(/nodes/*)+/value`\n- or-patterns `/node((/left), (/right))`\n- finite search in circular-data `**`\n- lookahead-rules to test selected property `?property:value` and regex values `?property:{\\d+}`\n- and typechecks `/value?:array`\n\n\n## Quick introduction\n\nBasically, a **query** is a json-pointer, which describes a path of properties into the json-data\n\n```js\nimport { get } from \"@sagold/json-query\";\nconst input = { object: { a: { id: \"id-a\" }, b: { id: \"id-b\" } } };\n\nconst values = get(input, \"/object/a/id\"); // [\"id-a\"]\n```\n\n\nBut each property may also be a glob-pattern or a regular expression:\n\n`*` selects all direct children\n\n```js\nconst input = { object: { a: { id: \"id-a\" }, b: { id: \"id-b\" } } };\n\nconst values = get(input, \"/object/*/id\"); // [\"id-a\", \"id-b\"]\n```\n\n\n`**` selects all values\n\n```js\nconst input = { object: { a: { id: \"id-a\" }, b: { id: \"id-b\" } } };\n\nconst values = get(input, \"/object/**\");\n// [ { a: { id: \"id-a\" }, b: { id: \"id-b\" } }, { id: \"id-a\" }, \"id-a\", { id: \"id-b\" }, \"id-b\" ]\n```\n\n\n`{}` calls a regular expression\n\n```js\nconst input = { object: { a: { id: \"id-a\" }, b: { id: \"id-b\" } } };\n\nconst values = get(input, \"/{obj.*}/{.*}/id\"); // [\"id-a\", \"id-b\"]\n```\n\n> Note. Regular expressions within strings, have to escape any backslashes, e.g. instead of `{\\d}` you need to pass `{\\\\d}`\n\n\n**lookahead** rules are used to validate the current value based on its properties\n\n`?child` tests if a childProperty is defined\n\n```js\nconst input = { object: { a: { id: \"id-a\" }, b: { id: \"id-b\" } } };\n\nconst values = get(input, \"/object/*?id\"); // [{ id: \"id-a\" }, { id: \"id-b\" }]\n```\n\n\n`?child:value` tests if a childProperty matches a value\n\n```js\nconst input = { object: { a: { id: \"id-a\" }, b: { id: \"id-b\" } } };\n\nconst values = get(input, \"/object/*?id:id-b\"); // [{ id: \"id-b\" }]\n```\n\nlookahead rules can also be negated `?child:!value`, tested by regex `?child:{^re+}`, combined `?child&&other` or joined `?child||other`. Undefined may be tested with `?property:undefined`, per default `undefined` is excluded from matches.\n\n\n**typechecks** can be used to query certain data-types\n\n`?: