Replace jsonpointer.dict() with Map implementation to avoid creating hidden classes #91
Description
Something like this:
import jsonpointer from 'json-pointer';
export function toJsonPointerMap(obj) {
const map = new Map();
jsonpointer.walk(obj, (value, pointer) => {
map.set(pointer, value);
});
return map;
}Generating a more useful structure might entail (to/from):
export function fromJsonPointerMap({map} = {}) {
assert(map, 'map', Map);
return _fromPointers({map});
}
// produces a map of deep pointers to primitives and sets; the values in each
// set share the same pointer value and if any value in the set is an object,
// it becomes a new map of deep pointers from that starting place; the pointer
// value for an empty objects will be an empty map
export function toJsonPointerMap({obj, flat = false} = {}) {
assert(obj, 'obj', 'object');
return _toPointers({cursor: obj, map: new Map(), flat});
}
export function _fromPointers({map} = {}) {
const result = {};
for(const [pointer, value] of map) {
// convert any non-primitive values
let val = value;
if(value instanceof Map) {
val = _fromPointers({map: value});
} else if(value instanceof Set) {
val = [...value].map(e => e instanceof Map ?
_fromPointers({map: e}) : e);
}
// if root pointer is used, `value` is result
if(pointer === '/') {
return val;
}
jsonpointer.set(result, pointer, val);
}
return result;
}
function _toPointers({
cursor, map, tokens = [], pointer = '/', flat = false
}) {
if(!flat && Array.isArray(cursor)) {
const set = new Set();
// when `map` is not set, case is array of arrays; return a new map
const result = map ? set : (map = new Map());
map.set(pointer, set);
for(const element of cursor) {
// reset map, tokens, and pointer for array elements
set.add(_toPointers({cursor: element, flat}));
}
return result;
}
if(cursor !== null && typeof cursor === 'object') {
map = map ?? new Map();
const entries = Object.entries(cursor);
if(entries.length === 0) {
// ensure empty object / array case is represented
map.set(pointer, Array.isArray(cursor) ? new Set() : new Map());
}
for(const [token, value] of entries) {
tokens.push(String(token));
pointer = jsonpointer.compile(tokens);
_toPointers({cursor: value, map, tokens, pointer, flat});
tokens.pop();
}
return map;
}
map?.set(pointer, cursor);
return cursor;
}