API · Core
Utilities
Small exported helpers used by Exstream operators and available to extensions.
Guards
| Function | Result |
|---|---|
isExstream(value) | Type guard for Exstream instances |
isExstreamPipeline(value) | Type guard for reusable pipelines |
isDefined(value) | False only for null and undefined |
has(value, property) | True for an own property on a defined value |
isIterable(value) | Has callable Symbol.iterator |
isAsyncIterable(value) | Has callable Symbol.asyncIterator |
isPromise(value) | Native Promise instance; generic thenables are false |
isFunction(value) | typeof value === 'function' |
isString(value) | Primitive string guard |
isError(value) | instanceof Error |
isNodeStream(value) | Runtime Node-stream shape guard |
Values and paths
get(object, fieldPath, defaultValue?)
makeGetter(fieldPath, defaultValue?)
splitFieldPath(path): string[]
traverse(value, pathParts, defaultValue?, index?): unknownPaths support dot and bracket notation. Traversal follows own properties only and returns the default when a segment is missing or the current value is nullish. Quotes inside bracket syntax are stripped; this is a lightweight field-path parser, not JSONPath.
Validation and functions
| Function | Contract |
|---|---|
asPositiveInteger(value, allowInfinity = false) | Coerces with Number; returns the positive integer/Infinity or null |
asNonNegativeFiniteNumber(value) | Coerces with Number; returns a finite number ≥ 0 or null |
escapeRegExp(text) | Escapes regex-significant and whitespace characters |
partial(fn, ...args) | Prepends arguments while preserving call-time this |
ncurry(count, fn, ...args) | Curries until count arguments, then ignores extras beyond that count |
curry(fn, ...args) | Uses fn.length as the curry count |
These helpers are public but low-level. Application code can use standard platform/library equivalents when their edge-case semantics are preferable.