bool startsWith(
Pattern pattern,
[int index = 0]
)

Returns true if this string starts with a match of pattern.

var string = 'Dart';
string.startsWith('D');                       // true
string.startsWith(new RegExp(r'[A-Z][a-z]')); // true

If index is provided, this method checks if the substring starting at that index starts with a match of pattern:

string.startsWith('art', 1);                  // true
string.startsWith(new RegExp(r'\w{3}'));      // true

index must not be negative or greater than length.

A RegExp containing '^' does not match if the index is greater than zero. The pattern works on the string as a whole, and does not extract a substring starting at index first:

string.startsWith(new RegExp(r'^art'), 1);    // false
string.startsWith(new RegExp(r'art'), 1);     // true

Source

/**
 * Returns true if this string starts with a match of [pattern].
 *
 *     var string = 'Dart';
 *     string.startsWith('D');                       // true
 *     string.startsWith(new RegExp(r'[A-Z][a-z]')); // true
 *
 * If [index] is provided, this method checks if the substring starting
 * at that index starts with a match of [pattern]:
 *
 *     string.startsWith('art', 1);                  // true
 *     string.startsWith(new RegExp(r'\w{3}'));      // true
 *
 * [index] must not be negative or greater than [length].
 *
 * A [RegExp] containing '^' does not match if the [index] is greater than
 * zero. The pattern works on the string as a whole, and does not extract
 * a substring starting at [index] first:
 *
 *     string.startsWith(new RegExp(r'^art'), 1);    // false
 *     string.startsWith(new RegExp(r'art'), 1);     // true
 */
bool startsWith(Pattern pattern, [int index = 0]);