fix(cast): --json support for erc20 cmds

crates/cast/src/cmd/erc20.rs

@@ -14,6 +14,7 @@ use foundry_cli::{
     opts::RpcOpts,
     utils::{LoadConfig, get_provider},
 };
+use foundry_common::shell;
 #[doc(hidden)]
 pub use foundry_config::utils::*;
 
@@ -241,7 +242,11 @@ impl Erc20Subcommand {
                     .call()
                     .await?;
 
-                sh_println!("{}", format_uint_exp(allowance))?
+                if shell::is_json() {
+                    sh_println!("{}", serde_json::to_string(&allowance.to_string())?)?
+                } else {
+                    sh_println!("{}", format_uint_exp(allowance))?
+                }
             }
             Self::Balance { token, owner, block, .. } => {
                 let provider = get_provider(&config)?;
@@ -253,7 +258,12 @@ impl Erc20Subcommand {
                     .block(block.unwrap_or_default())
                     .call()
                     .await?;
-                sh_println!("{}", format_uint_exp(balance))?
+
+                if shell::is_json() {
+                    sh_println!("{}", serde_json::to_string(&balance.to_string())?)?
+                } else {
+                    sh_println!("{}", format_uint_exp(balance))?
+                }
             }
             Self::Name { token, block, .. } => {
                 let provider = get_provider(&config)?;
@@ -264,7 +274,12 @@ impl Erc20Subcommand {
                     .block(block.unwrap_or_default())
                     .call()
                     .await?;
-                sh_println!("{}", name)?
+
+                if shell::is_json() {
+                    sh_println!("{}", serde_json::to_string(&name)?)?
+                } else {
+                    sh_println!("{}", name)?
+                }
             }
             Self::Symbol { token, block, .. } => {
                 let provider = get_provider(&config)?;
@@ -275,7 +290,12 @@ impl Erc20Subcommand {
                     .block(block.unwrap_or_default())
                     .call()
                     .await?;
-                sh_println!("{}", symbol)?
+
+                if shell::is_json() {
+                    sh_println!("{}", serde_json::to_string(&symbol)?)?
+                } else {
+                    sh_println!("{}", symbol)?
+                }
             }
             Self::Decimals { token, block, .. } => {
                 let provider = get_provider(&config)?;
@@ -297,7 +317,12 @@ impl Erc20Subcommand {
                     .block(block.unwrap_or_default())
                     .call()
                     .await?;
-                sh_println!("{}", format_uint_exp(total_supply))?
+
+                if shell::is_json() {
+                    sh_println!("{}", serde_json::to_string(&total_supply.to_string())?)?
+                } else {
+                    sh_println!("{}", format_uint_exp(total_supply))?
+                }
             }
             // State-changing
             Self::Transfer { token, to, amount, send_tx, .. } => {

crates/cast/tests/cli/erc20.rs

@@ -263,3 +263,108 @@ forgetest_async!(erc20_burn_success, |prj, cmd| {
     let total_supply: U256 = output.split_whitespace().next().unwrap().parse().unwrap();
     assert_eq!(total_supply, initial_supply - burn_amount);
 });
+
+// tests that `balance` command works correctly with --json flag
+forgetest_async!(erc20_balance_json, |prj, cmd| {
+    let (rpc, token) = setup_token_test(&prj, &mut cmd).await;
+
+    let output = cmd
+        .cast_fuse()
+        .args(["--json", "erc20", "balance", &token, anvil_const::ADDR1, "--rpc-url", &rpc])
+        .assert_success()
+        .get_output()
+        .stdout_lossy();
+
+    let balance_str: String = serde_json::from_str(&output).expect("valid json string");
+    let balance: U256 = balance_str.parse().unwrap();
+    assert_eq!(balance, U256::from(1_000_000_000_000_000_000_000u128));
+});
+
+// tests that `allowance` command works correctly with --json flag
+forgetest_async!(erc20_allowance_json, |prj, cmd| {
+    let (rpc, token) = setup_token_test(&prj, &mut cmd).await;
+
+    // First approve some tokens
+    let approve_amount = U256::from(50_000_000_000_000_000_000u128);
+    cmd.cast_fuse()
+        .args([
+            "erc20",
+            "approve",
+            &token,
+            anvil_const::ADDR2,
+            &approve_amount.to_string(),
+            "--rpc-url",
+            &rpc,
+            "--private-key",
+            anvil_const::PK1,
+        ])
+        .assert_success();
+
+    // Check allowance with JSON flag
+    let output = cmd
+        .cast_fuse()
+        .args([
+            "--json",
+            "erc20",
+            "allowance",
+            &token,
+            anvil_const::ADDR1,
+            anvil_const::ADDR2,
+            "--rpc-url",
+            &rpc,
+        ])
+        .assert_success()
+        .get_output()
+        .stdout_lossy();
+
+    let allowance_str: String = serde_json::from_str(&output).expect("valid json string");
+    let allowance: U256 = allowance_str.parse().unwrap();
+    assert_eq!(allowance, approve_amount);
+});
+
+// tests that `name`, `symbol`, `decimals`, and `totalSupply` commands work correctly with --json
+// flag
+forgetest_async!(erc20_metadata_json, |prj, cmd| {
+    let (rpc, token) = setup_token_test(&prj, &mut cmd).await;
+
+    // Test name with --json
+    let output = cmd
+        .cast_fuse()
+        .args(["--json", "erc20", "name", &token, "--rpc-url", &rpc])
+        .assert_success()
+        .get_output()
+        .stdout_lossy();
+    let name: String = serde_json::from_str(&output).expect("valid json string");
+    assert_eq!(name, "Test Token");
+
+    // Test symbol with --json
+    let output = cmd
+        .cast_fuse()
+        .args(["--json", "erc20", "symbol", &token, "--rpc-url", &rpc])
+        .assert_success()
+        .get_output()
+        .stdout_lossy();
+    let symbol: String = serde_json::from_str(&output).expect("valid json string");
+    assert_eq!(symbol, "TEST");
+
+    // Test decimals with --json
+    let output = cmd
+        .cast_fuse()
+        .args(["--json", "erc20", "decimals", &token, "--rpc-url", &rpc])
+        .assert_success()
+        .get_output()
+        .stdout_lossy();
+    let decimals: u8 = output.trim().parse().expect("valid number");
+    assert_eq!(decimals, 18);
+
+    // Test totalSupply with --json
+    let output = cmd
+        .cast_fuse()
+        .args(["--json", "erc20", "total-supply", &token, "--rpc-url", &rpc])
+        .assert_success()
+        .get_output()
+        .stdout_lossy();
+    let total_supply_str: String = serde_json::from_str(&output).expect("valid json string");
+    let total_supply: U256 = total_supply_str.parse().unwrap();
+    assert_eq!(total_supply, U256::from(1_000_000_000_000_000_000_000u128));
+});