create field class

src/field.ts

@@ -0,0 +1,45 @@
+import {
+  BigNumberish,
+  toBigInt,
+  toBeHex,
+  randomBytes,
+  zeroPadValue,
+} from 'ethers';
+
+const PRIME =
+  0x30644e72e131a029b85045b68181585d2833e84879b9709143e1f593f0000001n;
+
+export class Field {
+  public value: bigint;
+  constructor(_value: BigNumberish) {
+    this.value = toBigInt(_value);
+    if (this.value < 0n) {
+      while (this.value < 0n) {
+        this.value = this.value + PRIME;
+      }
+    }
+  }
+
+  static from(value: BigNumberish | Field): Field {
+    if (value instanceof Field) {
+      return value;
+    }
+    return new Field(value);
+  }
+
+  static zero() {
+    return new Field(0n);
+  }
+
+  add(other: Field): Field {
+    return new Field((this.value + other.value) % PRIME);
+  }
+
+  sub(other: Field): Field {
+    return new Field((this.value - other.value + PRIME) % PRIME);
+  }
+
+  mul(other: Field): Field {
+    return new Field((this.value * other.value) % PRIME);
+  }
+}